Cleanup mail(1)'s varying styles by converting to using style(9).

Also take a stab at cleaning up BDECFLAGS and convert all uses of
NOSTR, NIL, NONE, NOVAR, NOGRP, NOGE to NULL. Also kill 'register' to
get diffs somewhat closer to OpenBSD/NetBSD.

There are no functional changes however.
Reviewed by:	nra (visual inspection)

26 files changed, 1453 insertions, 1460 deletions

diff --git a/usr.bin/mail/aux.c b/usr.bin/mail/aux.c
index baeaa51..401399a 100644
--- a/usr.bin/mail/aux.c
+++ b/usr.bin/mail/aux.c
@@ -48,6 +48,8 @@ static const char rcsid[] =
  * Auxiliary functions.
  */
 
+static char *save2str __P((char *, char *));
+
 /*
  * Return a pointer to a dynamic copy of the argument.
  */
@@ -58,9 +60,9 @@ savestr(str)
 	char *new;
 	int size = strlen(str) + 1;
 
-	if ((new = salloc(size)) != NOSTR)
+	if ((new = salloc(size)) != NULL)
 		bcopy(str, new, size);
-	return new;
+	return (new);
 }
 
 /*
@@ -74,14 +76,14 @@ save2str(str, old)
 	int newsize = strlen(str) + 1;
 	int oldsize = old ? strlen(old) + 1 : 0;
 
-	if ((new = salloc(newsize + oldsize)) != NOSTR) {
+	if ((new = salloc(newsize + oldsize)) != NULL) {
 		if (oldsize) {
 			bcopy(old, new, oldsize);
 			new[oldsize - 1] = ' ';
 		}
 		bcopy(str, new + oldsize, newsize);
 	}
-	return new;
+	return (new);
 }
 
 /*
@@ -91,7 +93,7 @@ save2str(str, old)
  */
 void
 touch(mp)
-	register struct message *mp;
+	struct message *mp;
 {
 
 	mp->m_flag |= MTOUCH;
@@ -110,8 +112,8 @@ isdir(name)
 	struct stat sbuf;
 
 	if (stat(name, &sbuf) < 0)
-		return(0);
-	return(S_ISDIR(sbuf.st_mode));
+		return (0);
+	return (S_ISDIR(sbuf.st_mode));
 }
 
 /*
@@ -121,40 +123,40 @@ int
 argcount(argv)
 	char **argv;
 {
-	register char **ap;
+	char **ap;
 
-	for (ap = argv; *ap++ != NOSTR;)
+	for (ap = argv; *ap++ != NULL;)
 		;
-	return ap - argv - 1;
+	return (ap - argv - 1);
 }
 
 /*
  * Return the desired header line from the passed message
- * pointer (or NOSTR if the desired header field is not available).
+ * pointer (or NULL if the desired header field is not available).
  */
 char *
 hfield(field, mp)
-	char field[];
+	const char *field;
 	struct message *mp;
 {
-	register FILE *ibuf;
+	FILE *ibuf;
 	char linebuf[LINESIZE];
-	register int lc;
-	register char *hfield;
-	char *colon, *oldhfield = NOSTR;
+	int lc;
+	char *hfield;
+	char *colon, *oldhfield = NULL;
 
 	ibuf = setinput(mp);
 	if ((lc = mp->m_lines - 1) < 0)
-		return NOSTR;
+		return (NULL);
 	if (readline(ibuf, linebuf, LINESIZE) < 0)
-		return NOSTR;
+		return (NULL);
 	while (lc > 0) {
 		if ((lc = gethfield(ibuf, linebuf, lc, &colon)) < 0)
-			return oldhfield;
+			return (oldhfield);
 		if ((hfield = ishfield(linebuf, colon, field)) != NULL)
 			oldhfield = save2str(hfield, oldhfield);
 	}
-	return oldhfield;
+	return (oldhfield);
 }
 
 /*
@@ -165,22 +167,22 @@ hfield(field, mp)
  */
 int
 gethfield(f, linebuf, rem, colon)
-	register FILE *f;
+	FILE *f;
 	char linebuf[];
-	register int rem;
+	int rem;
 	char **colon;
 {
 	char line2[LINESIZE];
-	register char *cp, *cp2;
-	register int c;
+	char *cp, *cp2;
+	int c;
 
 	for (;;) {
 		if (--rem < 0)
-			return -1;
+			return (-1);
 		if ((c = readline(f, linebuf, LINESIZE)) <= 0)
-			return -1;
+			return (-1);
 		for (cp = linebuf; isprint(*cp) && *cp != ' ' && *cp != ':';
-		     cp++)
+		    cp++)
 			;
 		if (*cp != ':' || cp == linebuf)
 			continue;
@@ -212,7 +214,7 @@ gethfield(f, linebuf, rem, colon)
 			cp += c;
 		}
 		*cp = 0;
-		return rem;
+		return (rem);
 	}
 	/* NOTREACHED */
 }
@@ -224,20 +226,21 @@ gethfield(f, linebuf, rem, colon)
 
 char*
 ishfield(linebuf, colon, field)
-	char linebuf[], field[];
+	char linebuf[];
 	char *colon;
+	const char *field;
 {
-	register char *cp = colon;
+	char *cp = colon;
 
 	*cp = 0;
 	if (strcasecmp(linebuf, field) != 0) {
 		*cp = ':';
-		return 0;
+		return (0);
 	}
 	*cp = ':';
 	for (cp++; *cp == ' ' || *cp == '\t'; cp++)
 		;
-	return cp;
+	return (cp);
 }
 
 /*
@@ -246,7 +249,8 @@ ishfield(linebuf, colon, field)
  */
 void
 istrncpy(dest, src, dsize)
-	register char *dest, *src;
+	char *dest;
+	const char *src;
 	size_t dsize;
 {
 
@@ -282,16 +286,16 @@ source(arglist)
 	FILE *fi;
 	char *cp;
 
-	if ((cp = expand(*arglist)) == NOSTR)
-		return(1);
+	if ((cp = expand(*arglist)) == NULL)
+		return (1);
 	if ((fi = Fopen(cp, "r")) == NULL) {
 		warn("%s", cp);
-		return(1);
+		return (1);
 	}
 	if (ssp >= SSTACK_SIZE - 1) {
 		printf("Too much \"sourcing\" going on.\n");
-		Fclose(fi);
-		return(1);
+		(void)Fclose(fi);
+		return (1);
 	}
 	sstack[ssp].s_file = input;
 	sstack[ssp].s_cond = cond;
@@ -301,7 +305,7 @@ source(arglist)
 	cond = CANY;
 	input = fi;
 	sourcing++;
-	return(0);
+	return (0);
 }
 
 /*
@@ -314,9 +318,9 @@ unstack()
 	if (ssp <= 0) {
 		printf("\"Source\" stack over-pop.\n");
 		sourcing = 0;
-		return(1);
+		return (1);
 	}
-	Fclose(input);
+	(void)Fclose(input);
 	if (cond != CANY)
 		printf("Unmatched \"if\"\n");
 	ssp--;
@@ -325,7 +329,7 @@ unstack()
 	input = sstack[ssp].s_file;
 	if (ssp == 0)
 		sourcing = loading;
-	return(0);
+	return (0);
 }
 
 /*
@@ -338,7 +342,6 @@ alter(name)
 {
 	struct stat sb;
 	struct timeval tv[2];
-	time_t time();
 
 	if (stat(name, &sb))
 		return;
@@ -355,21 +358,21 @@ alter(name)
  */
 char *
 nameof(mp, reptype)
-	register struct message *mp;
+	struct message *mp;
 	int reptype;
 {
-	register char *cp, *cp2;
+	char *cp, *cp2;
 
 	cp = skin(name1(mp, reptype));
 	if (reptype != 0 || charcount(cp, '!') < 2)
-		return(cp);
+		return (cp);
 	cp2 = strrchr(cp, '!');
 	cp2--;
 	while (cp2 > cp && *cp2 != '!')
 		cp2--;
 	if (*cp2 == '!')
-		return(cp2 + 1);
-	return(cp);
+		return (cp2 + 1);
+	return (cp);
 }
 
 /*
@@ -378,9 +381,9 @@ nameof(mp, reptype)
  */
 char *
 skip_comment(cp)
-	register char *cp;
+	char *cp;
 {
-	register nesting = 1;
+	int nesting = 1;
 
 	for (; nesting > 0 && *cp; cp++) {
 		switch (*cp) {
@@ -396,7 +399,7 @@ skip_comment(cp)
 			break;
 		}
 	}
-	return cp;
+	return (cp);
 }
 
 /*
@@ -407,24 +410,22 @@ char *
 skin(name)
 	char *name;
 {
-	register int c;
-	register char *cp, *cp2;
-	char *bufend, *nbuf;
-	int gotlt, lastsp;
+	char *nbuf, *bufend, *cp, *cp2;
+	int c, gotlt, lastsp;
 
-	if (name == NOSTR)
-		return(NOSTR);
-	if (strchr(name, '(') == NOSTR && strchr(name, '<') == NOSTR
-	    && strchr(name, ' ') == NOSTR)
-		return(name);
+	if (name == NULL)
+		return (NULL);
+	if (strchr(name, '(') == NULL && strchr(name, '<') == NULL
+	    && strchr(name, ' ') == NULL)
+		return (name);
 
 	/* We assume that length(input) <= length(output) */
-	if ((nbuf = (char *)malloc(strlen(name) + 1)) == NULL)
+	if ((nbuf = malloc(strlen(name) + 1)) == NULL)
 		err(1, "Out of memory");
 	gotlt = 0;
 	lastsp = 0;
 	bufend = nbuf;
-	for (cp = name, cp2 = bufend; c = *cp++; ) {
+	for (cp = name, cp2 = bufend; (c = *cp++) != '\0'; ) {
 		switch (c) {
 		case '(':
 			cp = skip_comment(cp);
@@ -436,13 +437,13 @@ skin(name)
 			 * Start of a "quoted-string".
 			 * Copy it in its entirety.
 			 */
-			while (c = *cp) {
+			while ((c = *cp) != '\0') {
 				cp++;
 				if (c == '"')
 					break;
 				if (c != '\\')
 					*cp2++ = c;
-				else if (c = *cp) {
+				else if ((c = *cp) != '\0') {
 					*cp2++ = c;
 					cp++;
 				}
@@ -469,16 +470,16 @@ skin(name)
 		case '>':
 			if (gotlt) {
 				gotlt = 0;
-				while ((c = *cp) && c != ',') {
+				while ((c = *cp) != '\0' && c != ',') {
 					cp++;
 					if (c == '(')
 						cp = skip_comment(cp);
 					else if (c == '"')
-						while (c = *cp) {
+						while ((c = *cp) != '\0') {
 							cp++;
 							if (c == '"')
 								break;
-							if (c == '\\' && *cp)
+							if (c == '\\' && *cp != '\0')
 								cp++;
 						}
 				}
@@ -502,11 +503,11 @@ skin(name)
 			}
 		}
 	}
-	*cp2 = 0;
+	*cp2 = '\0';
 
-	if ((nbuf = (char *)realloc(nbuf, strlen(nbuf) + 1)) == NULL)
+	if ((nbuf = realloc(nbuf, strlen(nbuf) + 1)) == NULL)
 		err(1, "Out of memory");
-	return(nbuf);
+	return (nbuf);
 }
 
 /*
@@ -518,38 +519,39 @@ skin(name)
  */
 char *
 name1(mp, reptype)
-	register struct message *mp;
+	struct message *mp;
 	int reptype;
 {
 	char namebuf[LINESIZE];
 	char linebuf[LINESIZE];
-	register char *cp, *cp2;
-	register FILE *ibuf;
+	char *cp, *cp2;
+	FILE *ibuf;
 	int first = 1;
 
-	if ((cp = hfield("from", mp)) != NOSTR)
-		return cp;
-	if (reptype == 0 && (cp = hfield("sender", mp)) != NOSTR)
-		return cp;
+	if ((cp = hfield("from", mp)) != NULL)
+		return (cp);
+	if (reptype == 0 && (cp = hfield("sender", mp)) != NULL)
+		return (cp);
 	ibuf = setinput(mp);
 	namebuf[0] = '\0';
 	if (readline(ibuf, linebuf, LINESIZE) < 0)
-		return(savestr(namebuf));
+		return (savestr(namebuf));
 newname:
-	for (cp = linebuf; *cp && *cp != ' '; cp++)
+	for (cp = linebuf; *cp != '\0' && *cp != ' '; cp++)
 		;
 	for (; *cp == ' ' || *cp == '\t'; cp++)
 		;
 	for (cp2 = &namebuf[strlen(namebuf)];
-	     *cp && *cp != ' ' && *cp != '\t' && cp2 < namebuf + LINESIZE - 1;)
+	    *cp != '\0' && *cp != ' ' && *cp != '\t' &&
+	    cp2 < namebuf + LINESIZE - 1;)
 		*cp2++ = *cp++;
 	*cp2 = '\0';
 	if (readline(ibuf, linebuf, LINESIZE) < 0)
-		return(savestr(namebuf));
+		return (savestr(namebuf));
 	if ((cp = strchr(linebuf, 'F')) == NULL)
-		return(savestr(namebuf));
+		return (savestr(namebuf));
 	if (strncmp(cp, "From", 4) != 0)
-		return(savestr(namebuf));
+		return (savestr(namebuf));
 	while ((cp = strchr(cp, 'r')) != NULL) {
 		if (strncmp(cp, "remote", 6) == 0) {
 			if ((cp = strchr(cp, 'f')) == NULL)
@@ -570,7 +572,7 @@ newname:
 		}
 		cp++;
 	}
-	return(savestr(namebuf));
+	return (savestr(namebuf));
 }
 
 /*
@@ -581,13 +583,13 @@ charcount(str, c)
 	char *str;
 	int c;
 {
-	register char *cp;
-	register int i;
+	char *cp;
+	int i;
 
-	for (i = 0, cp = str; *cp; cp++)
+	for (i = 0, cp = str; *cp != '\0'; cp++)
 		if (*cp == c)
 			i++;
-	return(i);
+	return (i);
 }
 
 /*
@@ -595,13 +597,13 @@ charcount(str, c)
  */
 int
 isign(field, ignore)
-	char *field;
+	const char *field;
 	struct ignoretab ignore[2];
 {
 	char realfld[LINESIZE];
 
 	if (ignore == ignoreall)
-		return 1;
+		return (1);
 	/*
 	 * Lower-case the string, so that "Status" and "status"
 	 * will hash to the same place.
@@ -615,12 +617,12 @@ isign(field, ignore)
 
 int
 member(realfield, table)
-	register char *realfield;
+	char *realfield;
 	struct ignoretab *table;
 {
-	register struct ignore *igp;
+	struct ignore *igp;
 
-	for (igp = table->i_head[hash(realfield)]; igp != 0; igp = igp->i_link)
+	for (igp = table->i_head[hash(realfield)]; igp != NULL; igp = igp->i_link)
 		if (*igp->i_field == *realfield &&
 		    equal(igp->i_field, realfield))
 			return (1);
diff --git a/usr.bin/mail/cmd1.c b/usr.bin/mail/cmd1.c
index 0800d0a..aa5ad53 100644
--- a/usr.bin/mail/cmd1.c
+++ b/usr.bin/mail/cmd1.c
@@ -48,6 +48,8 @@ static const char rcsid[] =
  * User commands.
  */
 
+extern const struct cmd cmdtab[];
+
 /*
  * Print the current active headings.
  * Don't change dot if invoker didn't give an argument.
@@ -59,9 +61,8 @@ int
 headers(msgvec)
 	int *msgvec;
 {
-	register int n, mesg, flag;
-	register struct message *mp;
-	int size;
+	int n, mesg, flag, size;
+	struct message *mp;
 
 	size = screensize();
 	n = msgvec[0];
@@ -88,9 +89,9 @@ headers(msgvec)
 	}
 	if (flag == 0) {
 		printf("No more mail.\n");
-		return(1);
+		return (1);
 	}
-	return(0);
+	return (0);
 }
 
 /*
@@ -100,7 +101,7 @@ int
 scroll(arg)
 	char arg[];
 {
-	register int s, size;
+	int s, size;
 	int cur[1];
 
 	cur[0] = 0;
@@ -112,7 +113,7 @@ scroll(arg)
 		s++;
 		if (s * size > msgCount) {
 			printf("On last screenful of messages\n");
-			return(0);
+			return (0);
 		}
 		screen = s;
 		break;
@@ -120,16 +121,16 @@ scroll(arg)
 	case '-':
 		if (--s < 0) {
 			printf("On first screenful of messages\n");
-			return(0);
+			return (0);
 		}
 		screen = s;
 		break;
 
 	default:
 		printf("Unrecognized scrolling command \"%s\"\n", arg);
-		return(1);
+		return (1);
 	}
-	return(headers(cur));
+	return (headers(cur));
 }
 
 /*
@@ -141,9 +142,9 @@ screensize()
 	int s;
 	char *cp;
 
-	if ((cp = value("screen")) != NOSTR && (s = atoi(cp)) > 0)
-		return s;
-	return screenheight - 4;
+	if ((cp = value("screen")) != NULL && (s = atoi(cp)) > 0)
+		return (s);
+	return (screenheight - 4);
 }
 
 /*
@@ -154,13 +155,13 @@ int
 from(msgvec)
 	int *msgvec;
 {
-	register int *ip;
+	int *ip;
 
 	for (ip = msgvec; *ip != 0; ip++)
 		printhead(*ip);
 	if (--ip >= msgvec)
 		dot = &message[*ip - 1];
-	return(0);
+	return (0);
 }
 
 /*
@@ -179,8 +180,8 @@ printhead(mesg)
 	char *name;
 
 	mp = &message[mesg-1];
-	(void) readline(setinput(mp), headline, LINESIZE);
-	if ((subjline = hfield("subject", mp)) == NOSTR)
+	(void)readline(setinput(mp), headline, LINESIZE);
+	if ((subjline = hfield("subject", mp)) == NULL)
 		subjline = hfield("subj", mp);
 	/*
 	 * Bletch!
@@ -200,9 +201,9 @@ printhead(mesg)
 	parse(headline, &hl, pbuf);
 	sprintf(wcount, "%3ld/%-5ld", mp->m_lines, mp->m_size);
 	subjlen = screenwidth - 50 - strlen(wcount);
-	name = value("show-rcpt") != NOSTR ?
+	name = value("show-rcpt") != NULL ?
 		skin(hfield("to", mp)) : nameof(mp, 0);
-	if (subjline == NOSTR || subjlen < 0)		/* pretty pathetic */
+	if (subjline == NULL || subjlen < 0)		/* pretty pathetic */
 		printf("%c%c%3d %-20.20s  %16.16s %s\n",
 			curind, dispc, mesg, name, hl.l_date, wcount);
 	else
@@ -218,7 +219,7 @@ int
 pdot()
 {
 	printf("%d\n", dot - &message[0] + 1);
-	return(0);
+	return (0);
 }
 
 /*
@@ -227,9 +228,8 @@ pdot()
 int
 pcmdlist()
 {
-	register struct cmd *cp;
-	register int cc;
-	extern struct cmd cmdtab[];
+	const struct cmd *cp;
+	int cc;
 
 	printf("Commands are:\n");
 	for (cc = 0, cp = cmdtab; cp->c_name != NULL; cp++) {
@@ -238,12 +238,12 @@ pcmdlist()
 			printf("\n");
 			cc = strlen(cp->c_name) + 2;
 		}
-		if ((cp+1)->c_name != NOSTR)
+		if ((cp+1)->c_name != NULL)
 			printf("%s, ", cp->c_name);
 		else
 			printf("%s\n", cp->c_name);
 	}
-	return(0);
+	return (0);
 }
 
 /*
@@ -253,6 +253,7 @@ int
 more(msgvec)
 	int *msgvec;
 {
+
 	return (type1(msgvec, 1, 1));
 }
 
@@ -275,7 +276,7 @@ type(msgvec)
 	int *msgvec;
 {
 
-	return(type1(msgvec, 1, 0));
+	return (type1(msgvec, 1, 0));
 }
 
 /*
@@ -286,7 +287,7 @@ Type(msgvec)
 	int *msgvec;
 {
 
-	return(type1(msgvec, 0, 0));
+	return (type1(msgvec, 0, 0));
 }
 
 /*
@@ -298,17 +299,16 @@ type1(msgvec, doign, page)
 	int *msgvec;
 	int doign, page;
 {
-	register *ip;
-	register struct message *mp;
-	register char *cp;
-	int nlines;
+	int nlines, *ip;
+	struct message *mp;
+	char *cp;
 	FILE *obuf;
 
 	obuf = stdout;
 	if (setjmp(pipestop))
 		goto close_pipe;
-	if (value("interactive") != NOSTR &&
-	    (page || (cp = value("crt")) != NOSTR)) {
+	if (value("interactive") != NULL &&
+	    (page || (cp = value("crt")) != NULL)) {
 		nlines = 0;
 		if (!page) {
 			for (ip = msgvec; *ip && ip-msgvec < msgCount; ip++)
@@ -323,33 +323,40 @@ type1(msgvec, doign, page)
 				warnx("%s", cp);
 				obuf = stdout;
 			} else
-				signal(SIGPIPE, brokpipe);
+				(void)signal(SIGPIPE, brokpipe);
 		}
 	}
+
+	/*
+	 * Send messages to the output.
+	 *
+	 */
 	for (ip = msgvec; *ip && ip - msgvec < msgCount; ip++) {
 		mp = &message[*ip - 1];
 		touch(mp);
 		dot = mp;
-		if (value("quiet") == NOSTR)
+		if (value("quiet") == NULL)
 			fprintf(obuf, "Message %d:\n", *ip);
-		(void) sendmessage(mp, obuf, doign ? ignore : 0, NOSTR);
+		(void)sendmessage(mp, obuf, doign ? ignore : 0, NULL);
 	}
+
 close_pipe:
 	if (obuf != stdout) {
 		/*
 		 * Ignore SIGPIPE so it can't cause a duplicate close.
 		 */
-		signal(SIGPIPE, SIG_IGN);
-		Pclose(obuf);
-		signal(SIGPIPE, SIG_DFL);
+		(void)signal(SIGPIPE, SIG_IGN);
+		(void)Pclose(obuf);
+		(void)signal(SIGPIPE, SIG_DFL);
 	}
-	return(0);
+	return (0);
 }
 
 /*
  * Respond to a broken pipe signal --
  * probably caused by quitting more.
  */
+/*ARGSUSED*/
 void
 brokpipe(signo)
 	int signo;
@@ -366,15 +373,15 @@ int
 top(msgvec)
 	int *msgvec;
 {
-	register int *ip;
-	register struct message *mp;
+	int *ip;
+	struct message *mp;
 	int c, topl, lines, lineb;
 	char *valtop, linebuf[LINESIZE];
 	FILE *ibuf;
 
 	topl = 5;
 	valtop = value("toplines");
-	if (valtop != NOSTR) {
+	if (valtop != NULL) {
 		topl = atoi(valtop);
 		if (topl < 0 || topl > 10000)
 			topl = 5;
@@ -384,7 +391,7 @@ top(msgvec)
 		mp = &message[*ip - 1];
 		touch(mp);
 		dot = mp;
-		if (value("quiet") == NOSTR)
+		if (value("quiet") == NULL)
 			printf("Message %d:\n", *ip);
 		ibuf = setinput(mp);
 		c = mp->m_lines;
@@ -397,7 +404,7 @@ top(msgvec)
 			lineb = strspn(linebuf, " \t") == strlen(linebuf);
 		}
 	}
-	return(0);
+	return (0);
 }
 
 /*
@@ -408,14 +415,14 @@ int
 stouch(msgvec)
 	int msgvec[];
 {
-	register int *ip;
+	int *ip;
 
 	for (ip = msgvec; *ip != 0; ip++) {
 		dot = &message[*ip-1];
 		dot->m_flag |= MTOUCH;
 		dot->m_flag &= ~MPRESERVE;
 	}
-	return(0);
+	return (0);
 }
 
 /*
@@ -425,14 +432,14 @@ int
 mboxit(msgvec)
 	int msgvec[];
 {
-	register int *ip;
+	int *ip;
 
 	for (ip = msgvec; *ip != 0; ip++) {
 		dot = &message[*ip-1];
 		dot->m_flag |= MTOUCH|MBOX;
 		dot->m_flag &= ~MPRESERVE;
 	}
-	return(0);
+	return (0);
 }
 
 /*
@@ -446,10 +453,10 @@ folders()
 
 	if (getfold(dirname, sizeof(dirname)) < 0) {
 		printf("No value set for \"folder\"\n");
-		return 1;
+		return (1);
 	}
-	if ((cmd = value("LISTER")) == NOSTR)
+	if ((cmd = value("LISTER")) == NULL)
 		cmd = "ls";
-	(void) run_command(cmd, 0, -1, -1, dirname, NOSTR, NOSTR);
-	return 0;
+	(void)run_command(cmd, 0, -1, -1, dirname, NULL, NULL);
+	return (0);
 }
diff --git a/usr.bin/mail/cmd2.c b/usr.bin/mail/cmd2.c
index f74a06e..5ab6b85 100644
--- a/usr.bin/mail/cmd2.c
+++ b/usr.bin/mail/cmd2.c
@@ -49,6 +49,8 @@ static const char rcsid[] =
  * More user commands.
  */
 
+extern int wait_status;
+
 /*
  * If any arguments were given, go to the next applicable argument
  * following dot, otherwise, go to the next applicable message.
@@ -58,9 +60,8 @@ int
 next(msgvec)
 	int *msgvec;
 {
-	register struct message *mp;
-	register int *ip, *ip2;
-	int list[2], mdot;
+	struct message *mp;
+	int *ip, *ip2, list[2], mdot;
 
 	if (*msgvec != 0) {
 
@@ -95,7 +96,7 @@ next(msgvec)
 				ip2 = msgvec;
 		} while (ip2 != ip);
 		printf("No messages applicable\n");
-		return(1);
+		return (1);
 	}
 
 	/*
@@ -116,7 +117,7 @@ next(msgvec)
 			break;
 	if (mp >= &message[msgCount]) {
 		printf("At EOF\n");
-		return(0);
+		return (0);
 	}
 	dot = mp;
 hitit:
@@ -126,7 +127,7 @@ hitit:
 
 	list[0] = dot - &message[0] + 1;
 	list[1] = 0;
-	return(type(list));
+	return (type(list));
 }
 
 /*
@@ -138,7 +139,7 @@ save(str)
 	char str[];
 {
 
-	return save1(str, 1, "save", saveignore);
+	return (save1(str, 1, "save", saveignore));
 }
 
 /*
@@ -149,7 +150,7 @@ copycmd(str)
 	char str[];
 {
 
-	return save1(str, 0, "copy", saveignore);
+	return (save1(str, 0, "copy", saveignore));
 }
 
 /*
@@ -160,57 +161,57 @@ int
 save1(str, mark, cmd, ignore)
 	char str[];
 	int mark;
-	char *cmd;
+	const char *cmd;
 	struct ignoretab *ignore;
 {
-	register int *ip;
-	register struct message *mp;
-	char *file, *disp;
-	int f, *msgvec;
+	struct message *mp;
+	char *file;
+	const char *disp;
+	int f, *msgvec, *ip;
 	FILE *obuf;
 
-	msgvec = (int *) salloc((msgCount + 2) * sizeof *msgvec);
-	if ((file = snarf(str, &f)) == NOSTR)
-		return(1);
+	msgvec = (int *)salloc((msgCount + 2) * sizeof(*msgvec));
+	if ((file = snarf(str, &f)) == NULL)
+		return (1);
 	if (!f) {
 		*msgvec = first(0, MMNORM);
 		if (*msgvec == 0) {
 			printf("No messages to %s.\n", cmd);
-			return(1);
+			return (1);
 		}
 		msgvec[1] = 0;
 	}
 	if (f && getmsglist(str, msgvec, 0) < 0)
-		return(1);
-	if ((file = expand(file)) == NOSTR)
-		return(1);
+		return (1);
+	if ((file = expand(file)) == NULL)
+		return (1);
 	printf("\"%s\" ", file);
-	fflush(stdout);
+	(void)fflush(stdout);
 	if (access(file, 0) >= 0)
 		disp = "[Appended]";
 	else
 		disp = "[New file]";
 	if ((obuf = Fopen(file, "a")) == NULL) {
-		warn(NOSTR);
-		return(1);
+		warn((char *)NULL);
+		return (1);
 	}
 	for (ip = msgvec; *ip && ip-msgvec < msgCount; ip++) {
 		mp = &message[*ip - 1];
 		touch(mp);
-		if (sendmessage(mp, obuf, ignore, NOSTR) < 0) {
+		if (sendmessage(mp, obuf, ignore, NULL) < 0) {
 			warnx("%s", file);
-			Fclose(obuf);
-			return(1);
+			(void)Fclose(obuf);
+			return (1);
 		}
 		if (mark)
 			mp->m_flag |= MSAVED;
 	}
-	fflush(obuf);
+	(void)fflush(obuf);
 	if (ferror(obuf))
 		warn("%s", file);
-	Fclose(obuf);
+	(void)Fclose(obuf);
 	printf("%s\n", disp);
-	return(0);
+	return (0);
 }
 
 /*
@@ -222,13 +223,13 @@ swrite(str)
 	char str[];
 {
 
-	return save1(str, 1, "write", ignoreall);
+	return (save1(str, 1, "write", ignoreall));
 }
 
 /*
  * Snarf the file from the end of the command line and
  * return a pointer to it.  If there is no file attached,
- * just return NOSTR.  Put a null in front of the file
+ * just return NULL.  Put a null in front of the file
  * name so that the message list processing won't see it,
  * unless the file name is the only thing on the line, in
  * which case, return 0 in the reference flag variable.
@@ -239,7 +240,7 @@ snarf(linebuf, flag)
 	char linebuf[];
 	int *flag;
 {
-	register char *cp;
+	char *cp;
 
 	*flag = 1;
 	cp = strlen(linebuf) + linebuf - 1;
@@ -250,7 +251,7 @@ snarf(linebuf, flag)
 
 	while (cp > linebuf && isspace(*cp))
 		cp--;
-	*++cp = 0;
+	*++cp = '\0';
 
 	/*
 	 * Now search for the beginning of the file name.
@@ -260,13 +261,13 @@ snarf(linebuf, flag)
 		cp--;
 	if (*cp == '\0') {
 		printf("No file specified.\n");
-		return(NOSTR);
+		return (NULL);
 	}
 	if (isspace(*cp))
-		*cp++ = 0;
+		*cp++ = '\0';
 	else
 		*flag = 0;
-	return(cp);
+	return (cp);
 }
 
 /*
@@ -276,8 +277,9 @@ int
 delete(msgvec)
 	int msgvec[];
 {
+
 	delm(msgvec);
-	return 0;
+	return (0);
 }
 
 /*
@@ -296,12 +298,12 @@ deltype(msgvec)
 		if (list[0] > lastdot) {
 			touch(dot);
 			list[1] = 0;
-			return(type(list));
+			return (type(list));
 		}
 		printf("At EOF\n");
 	} else
 		printf("No more messages\n");
-	return(0);
+	return (0);
 }
 
 /*
@@ -313,9 +315,8 @@ int
 delm(msgvec)
 	int *msgvec;
 {
-	register struct message *mp;
-	register *ip;
-	int last;
+	struct message *mp;
+	int *ip, last;
 
 	last = 0;
 	for (ip = msgvec; *ip != 0; ip++) {
@@ -330,11 +331,11 @@ delm(msgvec)
 		last = first(0, MDELETED);
 		if (last != 0) {
 			dot = &message[last-1];
-			return(0);
+			return (0);
 		}
 		else {
 			dot = &message[0];
-			return(-1);
+			return (-1);
 		}
 	}
 
@@ -342,7 +343,7 @@ delm(msgvec)
 	 * Following can't happen -- it keeps lint happy
 	 */
 
-	return(-1);
+	return (-1);
 }
 
 /*
@@ -352,8 +353,8 @@ int
 undelete_messages(msgvec)
 	int *msgvec;
 {
-	register struct message *mp;
-	register *ip;
+	struct message *mp;
+	int *ip;
 
 	for (ip = msgvec; *ip && ip-msgvec < msgCount; ip++) {
 		mp = &message[*ip - 1];
@@ -361,7 +362,7 @@ undelete_messages(msgvec)
 		dot = mp;
 		mp->m_flag &= ~MDELETED;
 	}
-	return 0;
+	return (0);
 }
 
 /*
@@ -371,24 +372,23 @@ int
 core()
 {
 	int pid;
-	extern int wait_status;
 
 	switch (pid = fork()) {
 	case -1:
 		warn("fork");
-		return(1);
+		return (1);
 	case 0:
 		abort();
 		_exit(1);
 	}
 	printf("Okie dokie");
-	fflush(stdout);
+	(void)fflush(stdout);
 	wait_child(pid);
 	if (WIFSIGNALED(wait_status) && WCOREDUMP(wait_status))
 		printf(" -- Core dumped.\n");
 	else
 		printf(" -- Can't dump core.\n");
-	return 0;
+	return (0);
 }
 
 /*
@@ -398,14 +398,14 @@ int
 clobber(argv)
 	char **argv;
 {
-	register int times;
+	int times;
 
 	if (argv[0] == 0)
 		times = 1;
 	else
 		times = (atoi(argv[0]) + 511) / 512;
 	clob1(times);
-	return 0;
+	return (0);
 }
 
 /*
@@ -416,7 +416,7 @@ clob1(n)
 	int n;
 {
 	char buf[512];
-	register char *cp;
+	char *cp;
 
 	if (n <= 0)
 		return;
@@ -434,7 +434,7 @@ retfield(list)
 	char *list[];
 {
 
-	return ignore1(list, ignore + 1, "retained");
+	return (ignore1(list, ignore + 1, "retained"));
 }
 
 /*
@@ -446,7 +446,7 @@ igfield(list)
 	char *list[];
 {
 
-	return ignore1(list, ignore, "ignored");
+	return (ignore1(list, ignore, "ignored"));
 }
 
 int
@@ -454,7 +454,7 @@ saveretfield(list)
 	char *list[];
 {
 
-	return ignore1(list, saveignore + 1, "retained");
+	return (ignore1(list, saveignore + 1, "retained"));
 }
 
 int
@@ -462,36 +462,36 @@ saveigfield(list)
 	char *list[];
 {
 
-	return ignore1(list, saveignore, "ignored");
+	return (ignore1(list, saveignore, "ignored"));
 }
 
 int
 ignore1(list, tab, which)
 	char *list[];
 	struct ignoretab *tab;
-	char *which;
+	const char *which;
 {
 	char field[LINESIZE];
-	register int h;
-	register struct ignore *igp;
+	int h;
+	struct ignore *igp;
 	char **ap;
 
-	if (*list == NOSTR)
-		return igshow(tab, which);
+	if (*list == NULL)
+		return (igshow(tab, which));
 	for (ap = list; *ap != 0; ap++) {
 		istrncpy(field, *ap, sizeof(field));
 		if (member(field, tab))
 			continue;
 		h = hash(field);
-		igp = (struct ignore *) calloc(1, sizeof (struct ignore));
-		igp->i_field = calloc((unsigned) strlen(field) + 1,
-			sizeof (char));
+		igp = calloc(1, sizeof(struct ignore));
+		igp->i_field = calloc((unsigned)strlen(field) + 1,
+		    sizeof(char));
 		strcpy(igp->i_field, field);
 		igp->i_link = tab->i_head[h];
 		tab->i_head[h] = igp;
 		tab->i_count++;
 	}
-	return 0;
+	return (0);
 }
 
 /*
@@ -500,27 +500,26 @@ ignore1(list, tab, which)
 int
 igshow(tab, which)
 	struct ignoretab *tab;
-	char *which;
+	const char *which;
 {
-	register int h;
+	int h;
 	struct ignore *igp;
 	char **ap, **ring;
-	int igcomp();
 
 	if (tab->i_count == 0) {
 		printf("No fields currently being %s.\n", which);
-		return 0;
+		return (0);
 	}
-	ring = (char **) salloc((tab->i_count + 1) * sizeof (char *));
+	ring = (char **)salloc((tab->i_count + 1) * sizeof(char *));
 	ap = ring;
 	for (h = 0; h < HSHSIZE; h++)
-		for (igp = tab->i_head[h]; igp != 0; igp = igp->i_link)
+		for (igp = tab->i_head[h]; igp != NULL; igp = igp->i_link)
 			*ap++ = igp->i_field;
 	*ap = 0;
-	qsort(ring, tab->i_count, sizeof (char *), igcomp);
+	qsort(ring, tab->i_count, sizeof(char *), igcomp);
 	for (ap = ring; *ap != 0; ap++)
 		printf("%s\n", *ap);
-	return 0;
+	return (0);
 }
 
 /*
@@ -530,5 +529,6 @@ int
 igcomp(l, r)
 	const void *l, *r;
 {
-	return (strcmp(*(char **)l, *(char **)r));
+
+	return (strcmp(*(const char **)l, *(const char **)r));
 }
diff --git a/usr.bin/mail/cmd3.c b/usr.bin/mail/cmd3.c
index 36e42674..6cb5c1d 100644
--- a/usr.bin/mail/cmd3.c
+++ b/usr.bin/mail/cmd3.c
@@ -57,19 +57,19 @@ shell(str)
 	char *str;
 {
 	sig_t sigint = signal(SIGINT, SIG_IGN);
-	char *shell;
+	char *sh;
 	char cmd[BUFSIZ];
 
 	if (strlcpy(cmd, str, sizeof(cmd)) >= sizeof(cmd))
-		return 1;
+		return (1);
 	if (bangexp(cmd, sizeof(cmd)) < 0)
-		return 1;
-	if ((shell = value("SHELL")) == NOSTR)
-		shell = _PATH_CSHELL;
-	(void) run_command(shell, 0, -1, -1, "-c", cmd, NOSTR);
-	(void) signal(SIGINT, sigint);
+		return (1);
+	if ((sh = value("SHELL")) == NULL)
+		sh = _PATH_CSHELL;
+	(void)run_command(sh, 0, -1, -1, "-c", cmd, NULL);
+	(void)signal(SIGINT, sigint);
 	printf("!\n");
-	return 0;
+	return (0);
 }
 
 /*
@@ -81,14 +81,14 @@ dosh(str)
 	char *str;
 {
 	sig_t sigint = signal(SIGINT, SIG_IGN);
-	char *shell;
-
-	if ((shell = value("SHELL")) == NOSTR)
-		shell = _PATH_CSHELL;
-	(void) run_command(shell, 0, -1, -1, NOSTR, NOSTR, NOSTR);
-	(void) signal(SIGINT, sigint);
-	putchar('\n');
-	return 0;
+	char *sh;
+
+	if ((sh = value("SHELL")) == NULL)
+		sh = _PATH_CSHELL;
+	(void)run_command(sh, 0, -1, -1, NULL, NULL, NULL);
+	(void)signal(SIGINT, sigint);
+	printf("\n");
+	return (0);
 }
 
 /*
@@ -102,19 +102,18 @@ bangexp(str, strsize)
 {
 	char bangbuf[BUFSIZ];
 	static char lastbang[BUFSIZ];
-	register char *cp, *cp2;
-	register int n;
-	int changed = 0;
+	char *cp, *cp2;
+	int n, changed = 0;
 
 	cp = str;
 	cp2 = bangbuf;
 	n = sizeof(bangbuf);
-	while (*cp) {
+	while (*cp != '\0') {
 		if (*cp == '!') {
 			if (n < strlen(lastbang)) {
 overf:
 				printf("Command buffer overflow\n");
-				return(-1);
+				return (-1);
 			}
 			changed++;
 			if (strlcpy(cp2, lastbang, sizeof(bangbuf) - (cp2 - bangbuf))
@@ -139,13 +138,13 @@ overf:
 	*cp2 = 0;
 	if (changed) {
 		printf("!%s\n", bangbuf);
-		fflush(stdout);
+		(void)fflush(stdout);
 	}
 	if (strlcpy(str, bangbuf, strsize) >= strsize)
 		goto overf;
 	if (strlcpy(lastbang, bangbuf, sizeof(lastbang)) >= sizeof(lastbang))
 		goto overf;
-	return(0);
+	return (0);
 }
 
 /*
@@ -155,17 +154,17 @@ overf:
 int
 help()
 {
-	register c;
-	register FILE *f;
+	int c;
+	FILE *f;
 
 	if ((f = Fopen(_PATH_HELP, "r")) == NULL) {
 		warn("%s", _PATH_HELP);
-		return(1);
+		return (1);
 	}
 	while ((c = getc(f)) != EOF)
 		putchar(c);
-	Fclose(f);
-	return(0);
+	(void)Fclose(f);
+	return (0);
 }
 
 /*
@@ -177,25 +176,25 @@ schdir(arglist)
 {
 	char *cp;
 
-	if (*arglist == NOSTR) {
-		if (homedir == NOSTR)
-			return(1);
+	if (*arglist == NULL) {
+		if (homedir == NULL)
+			return (1);
 		cp = homedir;
 	} else
-		if ((cp = expand(*arglist)) == NOSTR)
-			return(1);
+		if ((cp = expand(*arglist)) == NULL)
+			return (1);
 	if (chdir(cp) < 0) {
 		warn("%s", cp);
-		return(1);
+		return (1);
 	}
-	return 0;
+	return (0);
 }
 
 int
 respond(msgvec)
 	int *msgvec;
 {
-	if (value("Replyall") == NOSTR)
+	if (value("Replyall") == NULL)
 		return (dorespond(msgvec));
 	else
 		return (doRespond(msgvec));
@@ -217,19 +216,19 @@ dorespond(msgvec)
 
 	if (msgvec[1] != 0) {
 		printf("Sorry, can't reply to multiple messages at once\n");
-		return(1);
+		return (1);
 	}
 	mp = &message[msgvec[0] - 1];
 	touch(mp);
 	dot = mp;
-	if ((rcv = skin(hfield("from", mp))) == NOSTR)
+	if ((rcv = skin(hfield("from", mp))) == NULL)
 		rcv = skin(nameof(mp, 1));
-	if ((replyto = skin(hfield("reply-to", mp))) != NOSTR)
+	if ((replyto = skin(hfield("reply-to", mp))) != NULL)
 		np = extract(replyto, GTO);
-	else if ((cp = skin(hfield("to", mp))) != NOSTR)
+	else if ((cp = skin(hfield("to", mp))) != NULL)
 		np = extract(cp, GTO);
 	else
-		np = NIL;
+		np = NULL;
 	np = elide(np);
 	/*
 	 * Delete my name from the reply list,
@@ -237,35 +236,35 @@ dorespond(msgvec)
 	 */
 	np = delname(np, myname);
 	if (altnames)
-		for (ap = altnames; *ap; ap++)
+		for (ap = altnames; *ap != NULL; ap++)
 			np = delname(np, *ap);
-	if (np != NIL && replyto == NOSTR)
+	if (np != NULL && replyto == NULL)
 		np = cat(np, extract(rcv, GTO));
-	else if (np == NIL) {
-		if (replyto != NOSTR)
+	else if (np == NULL) {
+		if (replyto != NULL)
 			printf("Empty reply-to field -- replying to author\n");
 		np = extract(rcv, GTO);
 	}
 	head.h_to = np;
-	if ((head.h_subject = hfield("subject", mp)) == NOSTR)
+	if ((head.h_subject = hfield("subject", mp)) == NULL)
 		head.h_subject = hfield("subj", mp);
 	head.h_subject = reedit(head.h_subject);
-	if (replyto == NOSTR && (cp = skin(hfield("cc", mp))) != NOSTR) {
+	if (replyto == NULL && (cp = skin(hfield("cc", mp))) != NULL) {
 		np = elide(extract(cp, GCC));
 		np = delname(np, myname);
 		if (altnames != 0)
-			for (ap = altnames; *ap; ap++)
+			for (ap = altnames; *ap != NULL; ap++)
 				np = delname(np, *ap);
 		head.h_cc = np;
 	} else
-		head.h_cc = NIL;
-	head.h_bcc = NIL;
-	head.h_smopts = NIL;
+		head.h_cc = NULL;
+	head.h_bcc = NULL;
+	head.h_smopts = NULL;
 	if ((head.h_replyto = getenv("REPLYTO")) == NULL)
-		head.h_replyto = NOSTR;
+		head.h_replyto = NULL;
 	head.h_inreplyto = skin(hfield("message-id", mp));
 	mail1(&head, 1);
-	return(0);
+	return (0);
 }
 
 /*
@@ -274,19 +273,19 @@ dorespond(msgvec)
  */
 char *
 reedit(subj)
-	register char *subj;
+	char *subj;
 {
 	char *newsubj;
 
-	if (subj == NOSTR)
-		return NOSTR;
+	if (subj == NULL)
+		return (NULL);
 	if ((subj[0] == 'r' || subj[0] == 'R') &&
 	    (subj[1] == 'e' || subj[1] == 'E') &&
 	    subj[2] == ':')
-		return subj;
+		return (subj);
 	newsubj = salloc(strlen(subj) + 5);
 	sprintf(newsubj, "Re: %s", subj);
-	return newsubj;
+	return (newsubj);
 }
 
 /*
@@ -297,12 +296,12 @@ int
 preserve(msgvec)
 	int *msgvec;
 {
-	register struct message *mp;
-	register int *ip, mesg;
+	int *ip, mesg;
+	struct message *mp;
 
 	if (edit) {
 		printf("Cannot \"preserve\" in edit mode\n");
-		return(1);
+		return (1);
 	}
 	for (ip = msgvec; *ip != 0; ip++) {
 		mesg = *ip;
@@ -311,7 +310,7 @@ preserve(msgvec)
 		mp->m_flag &= ~MBOX;
 		dot = mp;
 	}
-	return(0);
+	return (0);
 }
 
 /*
@@ -321,14 +320,14 @@ int
 unread(msgvec)
 	int	msgvec[];
 {
-	register int *ip;
+	int *ip;
 
 	for (ip = msgvec; *ip != 0; ip++) {
 		dot = &message[*ip-1];
 		dot->m_flag &= ~(MREAD|MTOUCH);
 		dot->m_flag |= MSTATUS;
 	}
-	return(0);
+	return (0);
 }
 
 /*
@@ -338,15 +337,15 @@ int
 messize(msgvec)
 	int *msgvec;
 {
-	register struct message *mp;
-	register int *ip, mesg;
+	struct message *mp;
+	int *ip, mesg;
 
 	for (ip = msgvec; *ip != 0; ip++) {
 		mesg = *ip;
 		mp = &message[mesg-1];
 		printf("%d: %ld/%ld\n", mesg, mp->m_lines, mp->m_size);
 	}
-	return(0);
+	return (0);
 }
 
 /*
@@ -358,7 +357,7 @@ rexit(e)
 	int e;
 {
 	if (sourcing)
-		return(1);
+		return (1);
 	exit(e);
 	/*NOTREACHED*/
 }
@@ -371,27 +370,27 @@ int
 set(arglist)
 	char **arglist;
 {
-	register struct var *vp;
-	register char *cp, *cp2;
+	struct var *vp;
+	char *cp, *cp2;
 	char varbuf[BUFSIZ], **ap, **p;
 	int errs, h, s;
 
-	if (*arglist == NOSTR) {
+	if (*arglist == NULL) {
 		for (h = 0, s = 1; h < HSHSIZE; h++)
-			for (vp = variables[h]; vp != NOVAR; vp = vp->v_link)
+			for (vp = variables[h]; vp != NULL; vp = vp->v_link)
 				s++;
-		ap = (char **) salloc(s * sizeof *ap);
+		ap = (char **)salloc(s * sizeof(*ap));
 		for (h = 0, p = ap; h < HSHSIZE; h++)
-			for (vp = variables[h]; vp != NOVAR; vp = vp->v_link)
+			for (vp = variables[h]; vp != NULL; vp = vp->v_link)
 				*p++ = vp->v_name;
-		*p = NOSTR;
+		*p = NULL;
 		sort(ap);
-		for (p = ap; *p != NOSTR; p++)
+		for (p = ap; *p != NULL; p++)
 			printf("%s\t%s\n", *p, value(*p));
-		return(0);
+		return (0);
 	}
 	errs = 0;
-	for (ap = arglist; *ap != NOSTR; ap++) {
+	for (ap = arglist; *ap != NULL; ap++) {
 		cp = *ap;
 		cp2 = varbuf;
 		while (cp2 < varbuf + sizeof(varbuf) - 1 && *cp != '=' && *cp != '\0')
@@ -408,7 +407,7 @@ set(arglist)
 		}
 		assign(varbuf, cp);
 	}
-	return(errs);
+	return (errs);
 }
 
 /*
@@ -418,13 +417,13 @@ int
 unset(arglist)
 	char **arglist;
 {
-	register struct var *vp, *vp2;
+	struct var *vp, *vp2;
 	int errs, h;
 	char **ap;
 
 	errs = 0;
-	for (ap = arglist; *ap != NOSTR; ap++) {
-		if ((vp2 = lookup(*ap)) == NOVAR) {
+	for (ap = arglist; *ap != NULL; ap++) {
+		if ((vp2 = lookup(*ap)) == NULL) {
 			if (!sourcing) {
 				printf("\"%s\": undefined variable\n", *ap);
 				errs++;
@@ -436,7 +435,7 @@ unset(arglist)
 			variables[h] = variables[h]->v_link;
 			vfree(vp2->v_name);
 			vfree(vp2->v_value);
-			free((char *)vp2);
+			(void)free(vp2);
 			continue;
 		}
 		for (vp = variables[h]; vp->v_link != vp2; vp = vp->v_link)
@@ -444,9 +443,9 @@ unset(arglist)
 		vp->v_link = vp2->v_link;
 		vfree(vp2->v_name);
 		vfree(vp2->v_value);
-		free((char *) vp2);
+		(void)free(vp2);
 	}
-	return(errs);
+	return (errs);
 }
 
 /*
@@ -456,36 +455,35 @@ int
 group(argv)
 	char **argv;
 {
-	register struct grouphead *gh;
-	register struct group *gp;
-	register int h;
-	int s;
+	struct grouphead *gh;
+	struct group *gp;
 	char **ap, *gname, **p;
+	int h, s;
 
-	if (*argv == NOSTR) {
+	if (*argv == NULL) {
 		for (h = 0, s = 1; h < HSHSIZE; h++)
-			for (gh = groups[h]; gh != NOGRP; gh = gh->g_link)
+			for (gh = groups[h]; gh != NULL; gh = gh->g_link)
 				s++;
-		ap = (char **) salloc(s * sizeof *ap);
+		ap = (char **)salloc(s * sizeof(*ap));
 		for (h = 0, p = ap; h < HSHSIZE; h++)
-			for (gh = groups[h]; gh != NOGRP; gh = gh->g_link)
+			for (gh = groups[h]; gh != NULL; gh = gh->g_link)
 				*p++ = gh->g_name;
-		*p = NOSTR;
+		*p = NULL;
 		sort(ap);
-		for (p = ap; *p != NOSTR; p++)
+		for (p = ap; *p != NULL; p++)
 			printgroup(*p);
-		return(0);
+		return (0);
 	}
-	if (argv[1] == NOSTR) {
+	if (argv[1] == NULL) {
 		printgroup(*argv);
-		return(0);
+		return (0);
 	}
 	gname = *argv;
 	h = hash(gname);
-	if ((gh = findgroup(gname)) == NOGRP) {
-		gh = (struct grouphead *) calloc(sizeof *gh, 1);
+	if ((gh = findgroup(gname)) == NULL) {
+		gh = calloc(sizeof(*gh), 1);
 		gh->g_name = vcopy(gname);
-		gh->g_list = NOGE;
+		gh->g_list = NULL;
 		gh->g_link = groups[h];
 		groups[h] = gh;
 	}
@@ -496,13 +494,13 @@ group(argv)
 	 * later anyway.
 	 */
 
-	for (ap = argv+1; *ap != NOSTR; ap++) {
-		gp = (struct group *) calloc(sizeof *gp, 1);
+	for (ap = argv+1; *ap != NULL; ap++) {
+		gp = calloc(sizeof(*gp), 1);
 		gp->ge_name = vcopy(*ap);
 		gp->ge_link = gh->g_list;
 		gh->g_list = gp;
 	}
-	return(0);
+	return (0);
 }
 
 /*
@@ -513,10 +511,9 @@ void
 sort(list)
 	char **list;
 {
-	register char **ap;
-	int diction();
+	char **ap;
 
-	for (ap = list; *ap != NOSTR; ap++)
+	for (ap = list; *ap != NULL; ap++)
 		;
 	if (ap-list < 2)
 		return;
@@ -531,7 +528,7 @@ int
 diction(a, b)
 	const void *a, *b;
 {
-	return(strcmp(*(char **)a, *(char **)b));
+	return (strcmp(*(const char **)a, *(const char **)b));
 }
 
 /*
@@ -543,7 +540,7 @@ int
 null(e)
 	int e;
 {
-	return 0;
+	return (0);
 }
 
 /*
@@ -552,17 +549,17 @@ null(e)
  */
 int
 file(argv)
-	register char **argv;
+	char **argv;
 {
 
-	if (argv[0] == NOSTR) {
+	if (argv[0] == NULL) {
 		newfileinfo();
-		return 0;
+		return (0);
 	}
 	if (setfile(*argv) < 0)
-		return 1;
+		return (1);
 	announce();
-	return 0;
+	return (0);
 }
 
 /*
@@ -572,26 +569,25 @@ int
 echo(argv)
 	char **argv;
 {
-	register char **ap;
-	register char *cp;
+	char **ap, *cp;
 
-	for (ap = argv; *ap != NOSTR; ap++) {
+	for (ap = argv; *ap != NULL; ap++) {
 		cp = *ap;
-		if ((cp = expand(cp)) != NOSTR) {
+		if ((cp = expand(cp)) != NULL) {
 			if (ap != argv)
-				putchar(' ');
+				printf(" ");
 			printf("%s", cp);
 		}
 	}
-	putchar('\n');
-	return 0;
+	printf("\n");
+	return (0);
 }
 
 int
 Respond(msgvec)
 	int *msgvec;
 {
-	if (value("Replyall") == NOSTR)
+	if (value("Replyall") == NULL)
 		return (doRespond(msgvec));
 	else
 		return (dorespond(msgvec));
@@ -608,34 +604,33 @@ doRespond(msgvec)
 {
 	struct header head;
 	struct message *mp;
-	register int *ap;
-	register char *cp;
-	char *mid;
+	int *ap;
+	char *cp, *mid;
 
-	head.h_to = NIL;
+	head.h_to = NULL;
 	for (ap = msgvec; *ap != 0; ap++) {
 		mp = &message[*ap - 1];
 		touch(mp);
 		dot = mp;
-		if ((cp = skin(hfield("from", mp))) == NOSTR)
+		if ((cp = skin(hfield("from", mp))) == NULL)
 			cp = skin(nameof(mp, 2));
 		head.h_to = cat(head.h_to, extract(cp, GTO));
 		mid = skin(hfield("message-id", mp));
 	}
-	if (head.h_to == NIL)
-		return 0;
+	if (head.h_to == NULL)
+		return (0);
 	mp = &message[msgvec[0] - 1];
-	if ((head.h_subject = hfield("subject", mp)) == NOSTR)
+	if ((head.h_subject = hfield("subject", mp)) == NULL)
 		head.h_subject = hfield("subj", mp);
 	head.h_subject = reedit(head.h_subject);
-	head.h_cc = NIL;
-	head.h_bcc = NIL;
-	head.h_smopts = NIL;
+	head.h_cc = NULL;
+	head.h_bcc = NULL;
+	head.h_smopts = NULL;
 	if ((head.h_replyto = getenv("REPLYTO")) == NULL)
-		head.h_replyto = NOSTR;
+		head.h_replyto = NULL;
 	head.h_inreplyto = mid;
 	mail1(&head, 1);
-	return 0;
+	return (0);
 }
 
 /*
@@ -646,11 +641,11 @@ int
 ifcmd(argv)
 	char **argv;
 {
-	register char *cp;
+	char *cp;
 
 	if (cond != CANY) {
 		printf("Illegal nested \"if\"\n");
-		return(1);
+		return (1);
 	}
 	cond = CANY;
 	cp = argv[0];
@@ -665,9 +660,9 @@ ifcmd(argv)
 
 	default:
 		printf("Unrecognized if-keyword: \"%s\"\n", cp);
-		return(1);
+		return (1);
 	}
-	return(0);
+	return (0);
 }
 
 /*
@@ -681,7 +676,7 @@ elsecmd()
 	switch (cond) {
 	case CANY:
 		printf("\"Else\" without matching \"if\"\n");
-		return(1);
+		return (1);
 
 	case CSEND:
 		cond = CRCV;
@@ -696,7 +691,7 @@ elsecmd()
 		cond = CANY;
 		break;
 	}
-	return(0);
+	return (0);
 }
 
 /*
@@ -708,10 +703,10 @@ endifcmd()
 
 	if (cond == CANY) {
 		printf("\"Endif\" without matching \"if\"\n");
-		return(1);
+		return (1);
 	}
 	cond = CANY;
-	return(0);
+	return (0);
 }
 
 /*
@@ -721,26 +716,26 @@ int
 alternates(namelist)
 	char **namelist;
 {
-	register int c;
-	register char **ap, **ap2, *cp;
+	int c;
+	char **ap, **ap2, *cp;
 
 	c = argcount(namelist) + 1;
 	if (c == 1) {
 		if (altnames == 0)
-			return(0);
-		for (ap = altnames; *ap; ap++)
+			return (0);
+		for (ap = altnames; *ap != NULL; ap++)
 			printf("%s ", *ap);
 		printf("\n");
-		return(0);
+		return (0);
 	}
 	if (altnames != 0)
-		free((char *) altnames);
-	altnames = (char **) calloc((unsigned) c, sizeof (char *));
-	for (ap = namelist, ap2 = altnames; *ap; ap++, ap2++) {
-		cp = (char *) calloc((unsigned) strlen(*ap) + 1, sizeof (char));
+		(void)free(altnames);
+	altnames = calloc((unsigned)c, sizeof(char *));
+	for (ap = namelist, ap2 = altnames; *ap != NULL; ap++, ap2++) {
+		cp = calloc((unsigned)strlen(*ap) + 1, sizeof(char));
 		strcpy(cp, *ap);
 		*ap2 = cp;
 	}
 	*ap2 = 0;
-	return(0);
+	return (0);
 }
diff --git a/usr.bin/mail/cmdtab.c b/usr.bin/mail/cmdtab.c
index 237bc98..d375b88 100644
--- a/usr.bin/mail/cmdtab.c
+++ b/usr.bin/mail/cmdtab.c
@@ -48,74 +48,77 @@ static const char rcsid[] =
  * Define all of the command names and bindings.
  */
 
-struct cmd cmdtab[] = {
-	"next",		next,		NDMLIST,	0,	MMNDEL,
-	"alias",	group,		M|RAWLIST,	0,	1000,
-	"print",	type,		MSGLIST,	0,	MMNDEL,
-	"type",		type,		MSGLIST,	0,	MMNDEL,
-	"Type",		Type,		MSGLIST,	0,	MMNDEL,
-	"Print",	Type,		MSGLIST,	0,	MMNDEL,
-	"visual",	visual,		I|MSGLIST,	0,	MMNORM,
-	"top",		top,		MSGLIST,	0,	MMNDEL,
-	"touch",	stouch,		W|MSGLIST,	0,	MMNDEL,
-	"preserve",	preserve,	W|MSGLIST,	0,	MMNDEL,
-	"delete",	delete,		W|P|MSGLIST,	0,	MMNDEL,
-	"dp",		deltype,	W|MSGLIST,	0,	MMNDEL,
-	"dt",		deltype,	W|MSGLIST,	0,	MMNDEL,
-	"undelete",	undelete_messages, P|MSGLIST,	MDELETED,MMNDEL,
-	"unset",	unset,		M|RAWLIST,	1,	1000,
-	"mail",		sendmail,	R|M|I|STRLIST,	0,	0,
-	"mbox",		mboxit,		W|MSGLIST,	0,	0,
-	"more",		more,		MSGLIST,	0,	MMNDEL,
-	"page",		more,		MSGLIST,	0,	MMNDEL,
-	"More",		More,		MSGLIST,	0,	MMNDEL,
-	"Page",		More,		MSGLIST,	0,	MMNDEL,
-	"unread",	unread,		MSGLIST,	0,	MMNDEL,
-	"!",		shell,		I|STRLIST,	0,	0,
-	"copy",		copycmd,	M|STRLIST,	0,	0,
-	"chdir",	schdir,		M|RAWLIST,	0,	1,
-	"cd",		schdir,		M|RAWLIST,	0,	1,
-	"save",		save,		STRLIST,	0,	0,
-	"source",	source,		M|RAWLIST,	1,	1,
-	"set",		set,		M|RAWLIST,	0,	1000,
-	"shell",	dosh,		I|NOLIST,	0,	0,
-	"version",	pversion,	M|NOLIST,	0,	0,
-	"group",	group,		M|RAWLIST,	0,	1000,
-	"write",	swrite,		STRLIST,	0,	0,
-	"from",		from,		MSGLIST,	0,	MMNORM,
-	"file",		file,		T|M|RAWLIST,	0,	1,
-	"folder",	file,		T|M|RAWLIST,	0,	1,
-	"folders",	folders,	T|M|NOLIST,	0,	0,
-	"?",		help,		M|NOLIST,	0,	0,
-	"z",		scroll,		M|STRLIST,	0,	0,
-	"headers",	headers,	MSGLIST,	0,	MMNDEL,
-	"help",		help,		M|NOLIST,	0,	0,
-	"=",		pdot,		NOLIST,		0,	0,
-	"Reply",	Respond,	R|I|MSGLIST,	0,	MMNDEL,
-	"Respond",	Respond,	R|I|MSGLIST,	0,	MMNDEL,
-	"reply",	respond,	R|I|MSGLIST,	0,	MMNDEL,
-	"respond",	respond,	R|I|MSGLIST,	0,	MMNDEL,
-	"edit",		editor,		I|MSGLIST,	0,	MMNORM,
-	"echo",		echo,		M|RAWLIST,	0,	1000,
-	"quit",		quitcmd,	NOLIST,		0,	0,
-	"list",		pcmdlist,	M|NOLIST,	0,	0,
-	"xit",		rexit,		M|NOLIST,	0,	0,
-	"exit",		rexit,		M|NOLIST,	0,	0,
-	"size",		messize,	MSGLIST,	0,	MMNDEL,
-	"hold",		preserve,	W|MSGLIST,	0,	MMNDEL,
-	"if",		ifcmd,		F|M|RAWLIST,	1,	1,
-	"else",		elsecmd,	F|M|RAWLIST,	0,	0,
-	"endif",	endifcmd,	F|M|RAWLIST,	0,	0,
-	"alternates",	alternates,	M|RAWLIST,	0,	1000,
-	"ignore",	igfield,	M|RAWLIST,	0,	1000,
-	"discard",	igfield,	M|RAWLIST,	0,	1000,
-	"retain",	retfield,	M|RAWLIST,	0,	1000,
-	"saveignore",	saveigfield,	M|RAWLIST,	0,	1000,
-	"savediscard",	saveigfield,	M|RAWLIST,	0,	1000,
-	"saveretain",	saveretfield,	M|RAWLIST,	0,	1000,
-/*	"Header",	Header,		STRLIST,	0,	1000,	*/
-	"core",		core,		M|NOLIST,	0,	0,
-	"#",		null,		M|NOLIST,	0,	0,
-	"clobber",	clobber,	M|RAWLIST,	0,	1,
-	0,		0,		0,		0,	0
+const struct cmd cmdtab[] = {
+	/*						msgmask msgflag  */
+	/* command	function	argtype		result	& mask   */
+	/* -------	--------	-------		------	-------  */
+	{ "next",	next,		NDMLIST,	0,	MMNDEL	},
+	{ "alias",	group,		M|RAWLIST,	0,	1000 	},
+	{ "print",	type,		MSGLIST,	0,	MMNDEL	},
+	{ "type",	type,		MSGLIST,	0,	MMNDEL	},
+	{ "Type",	Type,		MSGLIST,	0,	MMNDEL	},
+	{ "Print",	Type,		MSGLIST,	0,	MMNDEL	},
+	{ "visual",	visual,		I|MSGLIST,	0,	MMNORM	},
+	{ "top",	top,		MSGLIST,	0,	MMNDEL	},
+	{ "touch",	stouch,		W|MSGLIST,	0,	MMNDEL	},
+	{ "preserve",	preserve,	W|MSGLIST,	0,	MMNDEL	},
+	{ "delete",	delete,		W|P|MSGLIST,	0,	MMNDEL	},
+	{ "dp",		deltype,	W|MSGLIST,	0,	MMNDEL	},
+	{ "dt",		deltype,	W|MSGLIST,	0,	MMNDEL	},
+	{ "undelete",	undelete_messages, P|MSGLIST,	MDELETED,MMNDEL },
+	{ "unset",	unset,		M|RAWLIST,	1,	1000 	},
+	{ "mail",	sendmail,	R|M|I|STRLIST,	0,	0 	},
+	{ "mbox",	mboxit,		W|MSGLIST,	0,	0 	},
+	{ "more",	more,		MSGLIST,	0,	MMNDEL	},
+	{ "page",	more,		MSGLIST,	0,	MMNDEL	},
+	{ "More",	More,		MSGLIST,	0,	MMNDEL	},
+	{ "Page",	More,		MSGLIST,	0,	MMNDEL	},
+	{ "unread",	unread,		MSGLIST,	0,	MMNDEL	},
+	{ "!",		shell,		I|STRLIST,	0,	0	},
+	{ "copy",	copycmd,	M|STRLIST,	0,	0 	},
+	{ "chdir",	schdir,		M|RAWLIST,	0,	1 	},
+	{ "cd",		schdir,		M|RAWLIST,	0,	1 	},
+	{ "save",	save,		STRLIST,	0,	0	},
+	{ "source",	source,		M|RAWLIST,	1,	1	},
+	{ "set",	set,		M|RAWLIST,	0,	1000 	},
+	{ "shell",	dosh,		I|NOLIST,	0,	0 	},
+	{ "version",	pversion,	M|NOLIST,	0,	0 	},
+	{ "group",	group,		M|RAWLIST,	0,	1000 	},
+	{ "write",	swrite,		STRLIST,	0,	0 	},
+	{ "from",	from,		MSGLIST,	0,	MMNORM	},
+	{ "file",	file,		T|M|RAWLIST,	0,	1 	},
+	{ "folder",	file,		T|M|RAWLIST,	0,	1 	},
+	{ "folders",	folders,	T|M|NOLIST,	0,	0 	},
+	{ "?",		help,		M|NOLIST,	0,	0 	},
+	{ "z",		scroll,		M|STRLIST,	0,	0 	},
+	{ "headers",	headers,	MSGLIST,	0,	MMNDEL	},
+	{ "help",	help,		M|NOLIST,	0,	0 	},
+	{ "=",		pdot,		NOLIST,		0,	0 	},
+	{ "Reply",	Respond,	R|I|MSGLIST,	0,	MMNDEL	},
+	{ "Respond",	Respond,	R|I|MSGLIST,	0,	MMNDEL	},
+	{ "reply",	respond,	R|I|MSGLIST,	0,	MMNDEL	},
+	{ "respond",	respond,	R|I|MSGLIST,	0,	MMNDEL	},
+	{ "edit",	editor,		I|MSGLIST,	0,	MMNORM	},
+	{ "echo",	echo,		M|RAWLIST,	0,	1000 	},
+	{ "quit",	quitcmd,	NOLIST,		0,	0 	},
+	{ "list",	pcmdlist,	M|NOLIST,	0,	0 	},
+	{ "xit",	rexit,		M|NOLIST,	0,	0 	},
+	{ "exit",	rexit,		M|NOLIST,	0,	0 	},
+	{ "size",	messize,	MSGLIST,	0,	MMNDEL	},
+	{ "hold",	preserve,	W|MSGLIST,	0,	MMNDEL	},
+	{ "if",		ifcmd,		F|M|RAWLIST,	1,	1 	},
+	{ "else",	elsecmd,	F|M|RAWLIST,	0,	0 	},
+	{ "endif",	endifcmd,	F|M|RAWLIST,	0,	0 	},
+	{ "alternates",	alternates,	M|RAWLIST,	0,	1000 	},
+	{ "ignore",	igfield,	M|RAWLIST,	0,	1000 	},
+	{ "discard",	igfield,	M|RAWLIST,	0,	1000 	},
+	{ "retain",	retfield,	M|RAWLIST,	0,	1000 	},
+	{ "saveignore",	saveigfield,	M|RAWLIST,	0,	1000 	},
+	{ "savediscard",saveigfield,	M|RAWLIST,	0,	1000 	},
+	{ "saveretain",	saveretfield,	M|RAWLIST,	0,	1000 	},
+/*	{ "Header",	Header,		STRLIST,	0,	1000	}, */
+	{ "core",	core,		M|NOLIST,	0,	0 	},
+	{ "#",		null,		M|NOLIST,	0,	0 	},
+	{ "clobber",	clobber,	M|RAWLIST,	0,	1 	},
+	{ 0,		0,		0,		0,	0 	}
 };
diff --git a/usr.bin/mail/collect.c b/usr.bin/mail/collect.c
index 88c66dc..7331763 100644
--- a/usr.bin/mail/collect.c
+++ b/usr.bin/mail/collect.c
@@ -78,12 +78,9 @@ collect(hp, printheaders)
 	int printheaders;
 {
 	FILE *fbuf;
-	int lc, cc, escape, eofcount, fd;
-	register int c, t;
-	char linebuf[LINESIZE], tempname[PATHSIZE], *cp;
-	char getsub;
+	int lc, cc, escape, eofcount, fd, c, t;
+	char linebuf[LINESIZE], tempname[PATHSIZE], *cp, getsub;
 	int omask;
-	void collint(), collhup(), collstop();
 
 	collf = NULL;
 	/*
@@ -92,26 +89,27 @@ collect(hp, printheaders)
 	 */
 	omask = sigblock(sigmask(SIGINT) | sigmask(SIGHUP));
 	if ((saveint = signal(SIGINT, SIG_IGN)) != SIG_IGN)
-		signal(SIGINT, collint);
+		(void)signal(SIGINT, collint);
 	if ((savehup = signal(SIGHUP, SIG_IGN)) != SIG_IGN)
-		signal(SIGHUP, collhup);
+		(void)signal(SIGHUP, collhup);
 	savetstp = signal(SIGTSTP, collstop);
 	savettou = signal(SIGTTOU, collstop);
 	savettin = signal(SIGTTIN, collstop);
 	if (setjmp(collabort) || setjmp(colljmp)) {
-		rm(tempname);
+		(void)rm(tempname);
 		goto err;
 	}
 	sigsetmask(omask & ~(sigmask(SIGINT) | sigmask(SIGHUP)));
 
 	noreset++;
-	snprintf(tempname, sizeof(tempname), "%s/mail.RsXXXXXXXXXX", tmpdir);
+	(void)snprintf(tempname, sizeof(tempname),
+	    "%s/mail.RsXXXXXXXXXX", tmpdir);
 	if ((fd = mkstemp(tempname)) == -1 ||
 	    (collf = Fdopen(fd, "w+")) == NULL) {
 		warn("%s", tempname);
 		goto err;
 	}
-	rm(tempname);
+	(void)rm(tempname);
 
 	/*
 	 * If we are going to prompt for a subject,
@@ -120,14 +118,14 @@ collect(hp, printheaders)
 	 */
 	t = GTO|GSUBJECT|GCC|GNL;
 	getsub = 0;
-	if (hp->h_subject == NOSTR && value("interactive") != NOSTR &&
-	    (value("ask") != NOSTR || value("asksub") != NOSTR))
+	if (hp->h_subject == NULL && value("interactive") != NULL &&
+	    (value("ask") != NULL || value("asksub") != NULL))
 		t &= ~GNL, getsub++;
 	if (printheaders) {
 		puthead(hp, stdout, t);
-		fflush(stdout);
+		(void)fflush(stdout);
 	}
-	if ((cp = value("escape")) != NOSTR)
+	if ((cp = value("escape")) != NULL)
 		escape = *cp;
 	else
 		escape = ESCAPE;
@@ -145,12 +143,12 @@ collect(hp, printheaders)
 		 */
 cont:
 		if (hadintr) {
-			fflush(stdout);
+			(void)fflush(stdout);
 			fprintf(stderr,
 			"\n(Interrupt -- one more to kill letter)\n");
 		} else {
 			printf("(continue)\n");
-			fflush(stdout);
+			(void)fflush(stdout);
 		}
 	}
 	for (;;) {
@@ -158,8 +156,8 @@ cont:
 		c = readline(stdin, linebuf, LINESIZE);
 		colljmp_p = 0;
 		if (c < 0) {
-			if (value("interactive") != NOSTR &&
-			    value("ignoreeof") != NOSTR && ++eofcount < 25) {
+			if (value("interactive") != NULL &&
+			    value("ignoreeof") != NULL && ++eofcount < 25) {
 				printf("Use \".\" to terminate letter\n");
 				continue;
 			}
@@ -168,10 +166,10 @@ cont:
 		eofcount = 0;
 		hadintr = 0;
 		if (linebuf[0] == '.' && linebuf[1] == '\0' &&
-		    value("interactive") != NOSTR &&
-		    (value("dot") != NOSTR || value("ignoreeof") != NOSTR))
+		    value("interactive") != NULL &&
+		    (value("dot") != NULL || value("ignoreeof") != NULL))
 			break;
-		if (linebuf[0] != escape || value("interactive") == NOSTR) {
+		if (linebuf[0] != escape || value("interactive") == NULL) {
 			if (putline(collf, linebuf) < 0)
 				goto err;
 			continue;
@@ -286,7 +284,7 @@ cont:
 				break;
 			}
 			cp = expand(cp);
-			if (cp == NOSTR)
+			if (cp == NULL)
 				break;
 			if (isdir(cp)) {
 				printf("%s: Directory\n", cp);
@@ -297,18 +295,18 @@ cont:
 				break;
 			}
 			printf("\"%s\" ", cp);
-			fflush(stdout);
+			(void)fflush(stdout);
 			lc = 0;
 			cc = 0;
 			while (readline(fbuf, linebuf, LINESIZE) >= 0) {
 				lc++;
 				if ((t = putline(collf, linebuf)) < 0) {
-					Fclose(fbuf);
+					(void)Fclose(fbuf);
 					goto err;
 				}
 				cc += t;
 			}
-			Fclose(fbuf);
+			(void)Fclose(fbuf);
 			printf("%d/%d\n", lc, cc);
 			break;
 		case 'w':
@@ -322,7 +320,7 @@ cont:
 				fprintf(stderr, "Write what file!?\n");
 				break;
 			}
-			if ((cp = expand(cp)) == NOSTR)
+			if ((cp = expand(cp)) == NULL)
 				break;
 			rewind(collf);
 			exwrite(cp, collf, 1);
@@ -346,8 +344,8 @@ cont:
 				break;
 			}
 			while ((t = getc(fbuf)) != EOF)
-				(void) putchar(t);
-			Fclose(fbuf);
+				(void)putchar(t);
+			(void)Fclose(fbuf);
 			break;
 		case 'p':
 			/*
@@ -358,7 +356,7 @@ cont:
 			printf("-------\nMessage contains:\n");
 			puthead(hp, stdout, GTO|GSUBJECT|GCC|GBCC|GNL);
 			while ((t = getc(collf)) != EOF)
-				(void) putchar(t);
+				(void)putchar(t);
 			goto cont;
 		case '|':
 			/*
@@ -383,21 +381,21 @@ cont:
 	goto out;
 err:
 	if (collf != NULL) {
-		Fclose(collf);
+		(void)Fclose(collf);
 		collf = NULL;
 	}
 out:
 	if (collf != NULL)
 		rewind(collf);
 	noreset--;
-	sigblock(sigmask(SIGINT) | sigmask(SIGHUP));
-	signal(SIGINT, saveint);
-	signal(SIGHUP, savehup);
-	signal(SIGTSTP, savetstp);
-	signal(SIGTTOU, savettou);
-	signal(SIGTTIN, savettin);
-	sigsetmask(omask);
-	return collf;
+	(void)sigblock(sigmask(SIGINT) | sigmask(SIGHUP));
+	(void)signal(SIGINT, saveint);
+	(void)signal(SIGHUP, savehup);
+	(void)signal(SIGTSTP, savetstp);
+	(void)signal(SIGTTOU, savettou);
+	(void)signal(SIGTTIN, savettin);
+	(void)sigsetmask(omask);
+	return (collf);
 }
 
 /*
@@ -409,25 +407,24 @@ exwrite(name, fp, f)
 	FILE *fp;
 	int f;
 {
-	register FILE *of;
-	register int c;
+	FILE *of;
+	int c, lc;
 	long cc;
-	int lc;
 	struct stat junk;
 
 	if (f) {
 		printf("\"%s\" ", name);
-		fflush(stdout);
+		(void)fflush(stdout);
 	}
 	if (stat(name, &junk) >= 0 && S_ISREG(junk.st_mode)) {
 		if (!f)
 			fprintf(stderr, "%s: ", name);
 		fprintf(stderr, "File exists\n");
-		return(-1);
+		return (-1);
 	}
 	if ((of = Fopen(name, "w")) == NULL) {
-		warn(NOSTR);
-		return(-1);
+		warn((char *)NULL);
+		return (-1);
 	}
 	lc = 0;
 	cc = 0;
@@ -435,17 +432,17 @@ exwrite(name, fp, f)
 		cc++;
 		if (c == '\n')
 			lc++;
-		(void) putc(c, of);
+		(void)putc(c, of);
 		if (ferror(of)) {
 			warnx("%s", name);
-			Fclose(of);
-			return(-1);
+			(void)Fclose(of);
+			return (-1);
 		}
 	}
-	Fclose(of);
+	(void)Fclose(of);
 	printf("%d/%ld\n", lc, cc);
-	fflush(stdout);
-	return(0);
+	(void)fflush(stdout);
+	return (0);
 }
 
 /*
@@ -461,11 +458,11 @@ mesedit(fp, c)
 	FILE *nf = run_editor(fp, (off_t)-1, c, 0);
 
 	if (nf != NULL) {
-		fseek(nf, 0L, 2);
+		(void)fseek(nf, 0L, 2);
 		collf = nf;
-		Fclose(fp);
+		(void)Fclose(fp);
 	}
-	(void) signal(SIGINT, sigint);
+	(void)signal(SIGINT, sigint);
 }
 
 /*
@@ -482,39 +479,40 @@ mespipe(fp, cmd)
 	FILE *nf;
 	int fd;
 	sig_t sigint = signal(SIGINT, SIG_IGN);
-	char *shell, tempname[PATHSIZE];
+	char *sh, tempname[PATHSIZE];
 
-	snprintf(tempname, sizeof(tempname), "%s/mail.ReXXXXXXXXXX", tmpdir);
+	(void)snprintf(tempname, sizeof(tempname),
+	    "%s/mail.ReXXXXXXXXXX", tmpdir);
 	if ((fd = mkstemp(tempname)) == -1 ||
 	    (nf = Fdopen(fd, "w+")) == NULL) {
 		warn("%s", tempname);
 		goto out;
 	}
-	(void) rm(tempname);
+	(void)rm(tempname);
 	/*
 	 * stdin = current message.
 	 * stdout = new message.
 	 */
-	if ((shell = value("SHELL")) == NOSTR)
-		shell = _PATH_CSHELL;
-	if (run_command(shell,
-	    0, fileno(fp), fileno(nf), "-c", cmd, NOSTR) < 0) {
-		(void) Fclose(nf);
+	if ((sh = value("SHELL")) == NULL)
+		sh = _PATH_CSHELL;
+	if (run_command(sh,
+	    0, fileno(fp), fileno(nf), "-c", cmd, NULL) < 0) {
+		(void)Fclose(nf);
 		goto out;
 	}
 	if (fsize(nf) == 0) {
 		fprintf(stderr, "No bytes from \"%s\" !?\n", cmd);
-		(void) Fclose(nf);
+		(void)Fclose(nf);
 		goto out;
 	}
 	/*
 	 * Take new files.
 	 */
-	(void) fseek(nf, 0L, 2);
+	(void)fseek(nf, 0L, 2);
 	collf = nf;
-	(void) Fclose(fp);
+	(void)Fclose(fp);
 out:
-	(void) signal(SIGINT, sigint);
+	(void)signal(SIGINT, sigint);
 }
 
 /*
@@ -532,26 +530,26 @@ forward(ms, fp, fn, f)
 	char *fn;
 	int f;
 {
-	register int *msgvec;
+	int *msgvec;
 	struct ignoretab *ig;
 	char *tabst;
 
-	msgvec = (int *) salloc((msgCount+1) * sizeof *msgvec);
-	if (msgvec == (int *) NOSTR)
-		return(0);
+	msgvec = (int *)salloc((msgCount+1) * sizeof(*msgvec));
+	if (msgvec == NULL)
+		return (0);
 	if (getmsglist(ms, msgvec, 0) < 0)
-		return(0);
+		return (0);
 	if (*msgvec == 0) {
 		*msgvec = first(0, MMNORM);
 		if (*msgvec == 0) {
 			printf("No appropriate messages\n");
-			return(0);
+			return (0);
 		}
 		msgvec[1] = 0;
 	}
 	if (f == 'f' || f == 'F')
-		tabst = NOSTR;
-	else if ((tabst = value("indentprefix")) == NOSTR)
+		tabst = NULL;
+	else if ((tabst = value("indentprefix")) == NULL)
 		tabst = "\t";
 	ig = isupper(f) ? NULL : ignore;
 	printf("Interpolating:");
@@ -562,11 +560,11 @@ forward(ms, fp, fn, f)
 		printf(" %d", *msgvec);
 		if (sendmessage(mp, fp, ig, tabst) < 0) {
 			warnx("%s", fn);
-			return(-1);
+			return (-1);
 		}
 	}
 	printf("\n");
-	return(0);
+	return (0);
 }
 
 /*
@@ -579,10 +577,10 @@ collstop(s)
 {
 	sig_t old_action = signal(s, SIG_DFL);
 
-	sigsetmask(sigblock(0) & ~sigmask(s));
-	kill(0, s);
-	sigblock(sigmask(s));
-	signal(s, old_action);
+	(void)sigsetmask(sigblock(0) & ~sigmask(s));
+	(void)kill(0, s);
+	(void)sigblock(sigmask(s));
+	(void)signal(s, old_action);
 	if (colljmp_p) {
 		colljmp_p = 0;
 		hadintr = 0;
@@ -603,9 +601,9 @@ collint(s)
 	 * the control flow is subtle, because we can be called from ~q.
 	 */
 	if (!hadintr) {
-		if (value("ignore") != NOSTR) {
-			puts("@");
-			fflush(stdout);
+		if (value("ignore") != NULL) {
+			printf("@");
+			(void)fflush(stdout);
 			clearerr(stdin);
 			return;
 		}
@@ -613,7 +611,7 @@ collint(s)
 		longjmp(colljmp, 1);
 	}
 	rewind(collf);
-	if (value("nosave") == NOSTR)
+	if (value("nosave") == NULL)
 		savedeadletter(collf);
 	longjmp(collabort, 1);
 }
@@ -634,10 +632,10 @@ collhup(s)
 
 void
 savedeadletter(fp)
-	register FILE *fp;
+	FILE *fp;
 {
-	register FILE *dbuf;
-	register int c;
+	FILE *dbuf;
+	int c;
 	char *cp;
 
 	if (fsize(fp) == 0)
@@ -645,11 +643,11 @@ savedeadletter(fp)
 	cp = getdeadletter();
 	c = umask(077);
 	dbuf = Fopen(cp, "a");
-	(void) umask(c);
+	(void)umask(c);
 	if (dbuf == NULL)
 		return;
 	while ((c = getc(fp)) != EOF)
-		(void) putc(c, dbuf);
-	Fclose(dbuf);
+		(void)putc(c, dbuf);
+	(void)Fclose(dbuf);
 	rewind(fp);
 }
diff --git a/usr.bin/mail/def.h b/usr.bin/mail/def.h
index feb71eb..8b5e4ee 100644
--- a/usr.bin/mail/def.h
+++ b/usr.bin/mail/def.h
@@ -43,16 +43,18 @@
 
 #include <sys/param.h>
 #include <sys/stat.h>
-#include <sys/time.h>
 
-#include <signal.h>
-#include <termios.h>
-#include <unistd.h>
-#include <stdlib.h>
-#include <stdio.h>
 #include <ctype.h>
 #include <err.h>
+#include <paths.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
+#include <termios.h>
+#include <time.h>
+#include <unistd.h>
+
 #include "pathnames.h"
 
 #define	APPEND				/* New mail goes to end of mailbox */
@@ -62,9 +64,8 @@
 #define	PATHSIZE	MAXPATHLEN	/* Size of pathnames throughout */
 #define	HSHSIZE		59		/* Hash size for aliases and vars */
 #define	LINESIZE	BUFSIZ		/* max readable line width */
-#define	STRINGSIZE	((unsigned) 128)/* Dynamic allocation units */
+#define	STRINGSIZE	((unsigned)128)	/* Dynamic allocation units */
 #define	MAXARGC		1024		/* Maximum list of raw strings */
-#define	NOSTR		((char *) 0)	/* Null string pointer */
 #define	MAXEXP		25		/* Maximum expansion of aliases */
 
 #define	equal(a, b)	(strcmp(a,b)==0)/* A nice function to string compare */
@@ -96,8 +97,8 @@ struct message {
 /*
  * Given a file address, determine the block number it represents.
  */
-#define blockof(off)			((int) ((off) / 4096))
-#define boffsetof(off)			((int) ((off) % 4096))
+#define blockof(off)			((int)((off) / 4096))
+#define boffsetof(off)			((int)((off) % 4096))
 #define positionof(block, offset)	((off_t)(block) * 4096 + (offset))
 
 /*
@@ -106,7 +107,7 @@ struct message {
  * in lex.c
  */
 struct cmd {
-	char	*c_name;		/* Name of command */
+	const	char *c_name;		/* Name of command */
 	int	(*c_func)();		/* Implementor of the command */
 	short	c_argtype;		/* Type of arglist (see below) */
 	short	c_msgflag;		/* Required flags of messages */
@@ -173,13 +174,13 @@ struct headline {
  */
 
 struct header {
-	struct name *h_to;		/* Dynamic "To:" string */
-	char *h_subject;		/* Subject string */
-	struct name *h_cc;		/* Carbon copies string */
-	struct name *h_bcc;		/* Blind carbon copies */
-	char *h_replyto;		/* Reply address */
-	char *h_inreplyto;		/* Reference */
-	struct name *h_smopts;		/* Sendmail options */
+	struct	name *h_bcc;		/* Blind carbon copies */
+	struct	name *h_cc;		/* Carbon copies string */
+	struct	name *h_smopts;		/* Sendmail options */
+	struct	name *h_to;		/* Dynamic "To:" string */
+	char	*h_inreplyto;		/* Reference */
+	char	*h_replyto;		/* Reply address */
+	char	*h_subject;		/* Subject string */
 };
 
 /*
@@ -218,20 +219,14 @@ struct grouphead {
 	struct	group *g_list;		/* Users in group. */
 };
 
-#define	NIL	((struct name *) 0)	/* The nil pointer for namelists */
-#define	NONE	((struct cmd *) 0)	/* The nil pointer to command tab */
-#define	NOVAR	((struct var *) 0)	/* The nil pointer to variables */
-#define	NOGRP	((struct grouphead *) 0)/* The nil grouphead pointer */
-#define	NOGE	((struct group *) 0)	/* The nil group pointer */
-
 /*
  * Structure of the hash table of ignored header fields
  */
 struct ignoretab {
-	int i_count;			/* Number of entries */
-	struct ignore {
-		struct ignore *i_link;	/* Next ignored field in bucket */
-		char *i_field;		/* This ignored field */
+	int	i_count;			/* Number of entries */
+	struct	ignore {
+		struct	ignore *i_link;	/* Next ignored field in bucket */
+		char	*i_field;	/* This ignored field */
 	} *i_head[HSHSIZE];
 };
 
@@ -279,5 +274,5 @@ struct ignoretab {
  */
 #define trunc(stream) {							\
 	(void)fflush(stream); 						\
-	(void)ftruncate(fileno(stream), (long)ftell(stream));		\
+	(void)ftruncate(fileno(stream), (off_t)ftell(stream));		\
 }
diff --git a/usr.bin/mail/edit.c b/usr.bin/mail/edit.c
index 62103ad..2f3539b 100644
--- a/usr.bin/mail/edit.c
+++ b/usr.bin/mail/edit.c
@@ -59,7 +59,7 @@ editor(msgvec)
 	int *msgvec;
 {
 
-	return edit1(msgvec, 'e');
+	return (edit1(msgvec, 'e'));
 }
 
 /*
@@ -70,7 +70,7 @@ visual(msgvec)
 	int *msgvec;
 {
 
-	return edit1(msgvec, 'v');
+	return (edit1(msgvec, 'v'));
 }
 
 /*
@@ -83,10 +83,9 @@ edit1(msgvec, type)
 	int *msgvec;
 	int type;
 {
-	register int c;
-	int i;
+	int c, i;
 	FILE *fp;
-	register struct message *mp;
+	struct message *mp;
 	off_t size;
 
 	/*
@@ -100,7 +99,7 @@ edit1(msgvec, type)
 			char *p;
 
 			printf("Edit message %d [ynq]? ", msgvec[i]);
-			if (fgets(buf, sizeof buf, stdin) == 0)
+			if (fgets(buf, sizeof(buf), stdin) == 0)
 				break;
 			for (p = buf; *p == ' ' || *p == '\t'; p++)
 				;
@@ -114,7 +113,7 @@ edit1(msgvec, type)
 		sigint = signal(SIGINT, SIG_IGN);
 		fp = run_editor(setinput(mp), mp->m_size, type, readonly);
 		if (fp != NULL) {
-			(void) fseek(otf, 0L, 2);
+			(void)fseek(otf, 0L, 2);
 			size = ftell(otf);
 			mp->m_block = blockof(size);
 			mp->m_offset = boffsetof(size);
@@ -130,11 +129,11 @@ edit1(msgvec, type)
 			}
 			if (ferror(otf))
 				warnx("/tmp");
-			(void) Fclose(fp);
+			(void)Fclose(fp);
 		}
-		(void) signal(SIGINT, sigint);
+		(void)signal(SIGINT, sigint);
 	}
-	return 0;
+	return (0);
 }
 
 /*
@@ -145,17 +144,18 @@ edit1(msgvec, type)
  */
 FILE *
 run_editor(fp, size, type, readonly)
-	register FILE *fp;
+	FILE *fp;
 	off_t size;
 	int type, readonly;
 {
-	register FILE *nf = NULL;
-	register int t;
+	FILE *nf = NULL;
+	int t;
 	time_t modtime;
 	char *edit, tempname[PATHSIZE];
 	struct stat statb;
 
-	snprintf(tempname, sizeof(tempname), "%s/mail.ReXXXXXXXXXX", tmpdir);
+	(void)snprintf(tempname, sizeof(tempname),
+	    "%s/mail.ReXXXXXXXXXX", tmpdir);
 	if ((t = mkstemp(tempname)) == -1 ||
 	    (nf = Fdopen(t, "w")) == NULL) {
 		warn("%s", tempname);
@@ -163,38 +163,38 @@ run_editor(fp, size, type, readonly)
 	}
 	if (readonly && fchmod(t, 0400) == -1) {
 		warn("%s", tempname);
-		(void) rm(tempname);
+		(void)rm(tempname);
 		goto out;
 	}
 	if (size >= 0)
 		while (--size >= 0 && (t = getc(fp)) != EOF)
-			(void) putc(t, nf);
+			(void)putc(t, nf);
 	else
 		while ((t = getc(fp)) != EOF)
-			(void) putc(t, nf);
-	(void) fflush(nf);
+			(void)putc(t, nf);
+	(void)fflush(nf);
 	if (fstat(fileno(nf), &statb) < 0)
 		modtime = 0;
 	else
 		modtime = statb.st_mtime;
 	if (ferror(nf)) {
-		(void) Fclose(nf);
+		(void)Fclose(nf);
 		warnx("%s", tempname);
-		(void) rm(tempname);
+		(void)rm(tempname);
 		nf = NULL;
 		goto out;
 	}
 	if (Fclose(nf) < 0) {
 		warn("%s", tempname);
-		(void) rm(tempname);
+		(void)rm(tempname);
 		nf = NULL;
 		goto out;
 	}
 	nf = NULL;
-	if ((edit = value(type == 'e' ? "EDITOR" : "VISUAL")) == NOSTR)
+	if ((edit = value(type == 'e' ? "EDITOR" : "VISUAL")) == NULL)
 		edit = type == 'e' ? _PATH_EX : _PATH_VI;
-	if (run_command(edit, 0, -1, -1, tempname, NOSTR, NOSTR) < 0) {
-		(void) rm(tempname);
+	if (run_command(edit, 0, -1, -1, tempname, NULL, NULL) < 0) {
+		(void)rm(tempname);
 		goto out;
 	}
 	/*
@@ -202,7 +202,7 @@ run_editor(fp, size, type, readonly)
 	 * temporary and return.
 	 */
 	if (readonly) {
-		(void) rm(tempname);
+		(void)rm(tempname);
 		goto out;
 	}
 	if (stat(tempname, &statb) < 0) {
@@ -210,7 +210,7 @@ run_editor(fp, size, type, readonly)
 		goto out;
 	}
 	if (modtime == statb.st_mtime) {
-		(void) rm(tempname);
+		(void)rm(tempname);
 		goto out;
 	}
 	/*
@@ -218,10 +218,10 @@ run_editor(fp, size, type, readonly)
 	 */
 	if ((nf = Fopen(tempname, "a+")) == NULL) {
 		warn("%s", tempname);
-		(void) rm(tempname);
+		(void)rm(tempname);
 		goto out;
 	}
-	(void) rm(tempname);
+	(void)rm(tempname);
 out:
-	return nf;
+	return (nf);
 }
diff --git a/usr.bin/mail/extern.h b/usr.bin/mail/extern.h
index 62de161..cbd622c 100644
--- a/usr.bin/mail/extern.h
+++ b/usr.bin/mail/extern.h
@@ -45,22 +45,22 @@ struct name *outof __P((struct name *, FILE *, struct header *));
 struct name *put __P((struct name *, struct name *));
 struct name *tailof __P((struct name *));
 struct name *usermap __P((struct name *));
-FILE	*Fdopen __P((int, char *));
-FILE	*Fopen __P((char *, char *));
-FILE	*Popen __P((char *, char *));
+FILE	*Fdopen __P((int, const char *));
+FILE	*Fopen __P((const char *, const char *));
+FILE	*Popen __P((char *, const char *));
 FILE	*collect __P((struct header *, int));
 char	*copyin __P((char *, char **));
 char	*detract __P((struct name *, int));
 char	*expand __P((char *));
 char	*getdeadletter __P((void));
 char	*getname __P((int));
-char	*hfield __P((char [], struct message *));
+char	*hfield __P((const char *, struct message *));
 FILE	*infix __P((struct header *, FILE *));
-char	*ishfield __P((char [], char[], char *));
+char	*ishfield __P((char [], char *, const char *));
 char	*name1 __P((struct message *, int));
 char	*nameof __P((struct message *, int));
 char	*nextword __P((char *, char *));
-char	*readtty __P((char [], char []));
+char	*readtty __P((const char *, char []));
 char 	*reedit __P((char *));
 FILE	*run_editor __P((FILE *, off_t, int, int));
 char	*salloc __P((int));
@@ -70,8 +70,8 @@ char	*skin __P((char *));
 char	*skip_comment __P((char *));
 char	*snarf __P((char [], int *));
 char	*username __P((void));
-char	*value __P((char []));
-char	*vcopy __P((char []));
+char	*value __P((const char *));
+char	*vcopy __P((const char *));
 char	*yankword __P((char *, char []));
 int	 Fclose __P((FILE *));
 int	 More __P((int *));
@@ -85,7 +85,7 @@ int	 alternates __P((char **));
 void	 announce __P((void));
 int	 append __P((struct message *, FILE *));
 int	 argcount __P((char **));
-void	 assign __P((char [], char []));
+void	 assign __P((const char *, const char *));
 int	 bangexp __P((char *, size_t));
 void	 brokpipe __P((int));
 int	 charcount __P((char *, int));
@@ -116,14 +116,14 @@ int	 endifcmd __P((void));
 int	 evalcol __P((int));
 int	 execute __P((char [], int));
 int	 exwrite __P((char [], FILE *, int));
-void	 fail __P((char [], char []));
+void	 fail __P((const char *, const char *));
 int	 file __P((char **));
 struct grouphead *
 	 findgroup __P((char []));
 void	 findmail __P((char *, char *, int));
 int	 first __P((int, int));
 void	 fixhead __P((struct header *, struct name *));
-void	 fmt __P((char *, struct name *, FILE *, int));
+void	 fmt __P((const char *, struct name *, FILE *, int));
 int	 folders __P((void));
 int	 forward __P((char [], FILE *, char *, int));
 void	 free_child __P((int));
@@ -137,7 +137,7 @@ int	 getuserid __P((char []));
 int	 grabh __P((struct header *, int));
 int	 group __P((char **));
 void	 hangup __P((int));
-int	 hash __P((char *));
+int	 hash __P((const char *));
 void	 hdrstop __P((int));
 int	 headers __P((int *));
 int	 help __P((void));
@@ -145,21 +145,21 @@ void	 holdsigs __P((void));
 int	 ifcmd __P((char **));
 int	 igcomp __P((const void *, const void *));
 int	 igfield __P((char *[]));
-int	 ignore1 __P((char *[], struct ignoretab *, char *));
-int	 igshow __P((struct ignoretab *, char *));
+int	 ignore1 __P((char *[], struct ignoretab *, const char *));
+int	 igshow __P((struct ignoretab *, const char *));
 void	 intr __P((int));
 int	 isdate __P((char []));
 int	 isdir __P((char []));
 int	 isfileaddr __P((char *));
 int	 ishead __P((char []));
-int	 isign __P((char *, struct ignoretab []));
-int	 isprefix __P((char *, char *));
-void	 istrncpy __P((char *, char *, size_t));
-struct cmd *
+int	 isign __P((const char *, struct ignoretab []));
+int	 isprefix __P((const char *, const char *));
+void	 istrncpy __P((char *, const char *, size_t));
+__const struct cmd *
 	 lex __P((char []));
 void	 load __P((char *));
 struct var *
-	 lookup __P((char []));
+	 lookup __P((const char *));
 int	 mail __P((struct name *,
 	    struct name *, struct name *, struct name *, char *, char *));
 void	 mail1 __P((struct header *, int));
@@ -201,7 +201,7 @@ int	 rexit __P((int));
 int	 rm __P((char *));
 int	 run_command __P((char *, int, int, int, char *, char *, char *));
 int	 save __P((char []));
-int	 save1 __P((char [], int, char *, struct ignoretab *));
+int	 save1 __P((char [], int, const char *, struct ignoretab *));
 void	 savedeadletter __P((FILE *));
 int	 saveigfield __P((char *[]));
 int	 savemail __P((char [], FILE *));
diff --git a/usr.bin/mail/fio.c b/usr.bin/mail/fio.c
index fe6480a..67413b5 100644
--- a/usr.bin/mail/fio.c
+++ b/usr.bin/mail/fio.c
@@ -56,15 +56,17 @@ static const char rcsid[] =
  * File I/O.
  */
 
+extern int wait_status;
+
 /*
  * Set up the input pointers while copying the mail file into /tmp.
  */
 void
 setptr(ibuf)
-	register FILE *ibuf;
+	FILE *ibuf;
 {
-	register int c, count;
-	register char *cp, *cp2;
+	int c, count;
+	char *cp, *cp2;
 	struct message this;
 	FILE *mestmp;
 	off_t offset;
@@ -75,7 +77,7 @@ setptr(ibuf)
 	(void)snprintf(pathbuf, sizeof(pathbuf), "%s/mail.XXXXXXXXXX", tmpdir);
 	if ((c = mkstemp(pathbuf)) == -1 || (mestmp = Fdopen(c, "r+")) == NULL)
 		err(1, "can't open %s", pathbuf);
-	(void) rm(pathbuf);
+	(void)rm(pathbuf);
 
 	msgCount = 0;
 	maybe = 1;
@@ -104,7 +106,7 @@ setptr(ibuf)
 			linebuf[count - 1] = '\n';
 		}
 
-		(void) fwrite(linebuf, sizeof *linebuf, count, otf);
+		(void)fwrite(linebuf, sizeof(*linebuf), count, otf);
 		if (ferror(otf))
 			errx(1, "/tmp");
 		if (count)
@@ -123,12 +125,12 @@ setptr(ibuf)
 			inhead = 0;
 		} else if (inhead) {
 			for (cp = linebuf, cp2 = "status";; cp++) {
-				if ((c = *cp2++) == 0) {
+				if ((c = *cp2++) == '\0') {
 					while (isspace(*cp++))
 						;
 					if (cp[-1] != ':')
 						break;
-					while (c = *cp++)
+					while ((c = *cp++) != '\0')
 						if (c == 'R')
 							this.m_flag |= MREAD;
 						else if (c == 'O')
@@ -157,11 +159,11 @@ putline(obuf, linebuf)
 	FILE *obuf;
 	char *linebuf;
 {
-	register int c;
+	int c;
 
 	c = strlen(linebuf);
-	(void) fwrite(linebuf, sizeof *linebuf, c, obuf);
-	(void) putc('\n', obuf);
+	(void)fwrite(linebuf, sizeof(*linebuf), c, obuf);
+	fprintf(obuf, "\n");
 	if (ferror(obuf))
 		return (-1);
 	return (c + 1);
@@ -178,17 +180,17 @@ readline(ibuf, linebuf, linesize)
 	char *linebuf;
 	int linesize;
 {
-	register int n;
+	int n;
 
 	clearerr(ibuf);
 	if (fgets(linebuf, linesize, ibuf) == NULL)
-		return -1;
+		return (-1);
 	n = strlen(linebuf);
 	if (n > 0 && linebuf[n - 1] == '\n')
 		linebuf[--n] = '\0';
 	if (n > 0 && linebuf[n - 1] == '\r')
 		linebuf[--n] = '\0';
-	return n;
+	return (n);
 }
 
 /*
@@ -197,10 +199,10 @@ readline(ibuf, linebuf, linesize)
  */
 FILE *
 setinput(mp)
-	register struct message *mp;
+	struct message *mp;
 {
 
-	fflush(otf);
+	(void)fflush(otf);
 	if (fseek(itf, (long)positionof(mp->m_block, mp->m_offset), 0) < 0)
 		err(1, "fseek");
 	return (itf);
@@ -214,21 +216,21 @@ void
 makemessage(f)
 	FILE *f;
 {
-	register size = (msgCount + 1) * sizeof (struct message);
+	int size = (msgCount + 1) * sizeof(struct message);
 
 	if (message != 0)
-		free((char *) message);
-	if ((message = (struct message *) malloc((unsigned) size)) == 0)
+		(void)free(message);
+	if ((message = malloc((unsigned)size)) == NULL)
 		err(1, "Out of memory");
 	dot = message;
-	size -= sizeof (struct message);
-	fflush(f);
-	(void) lseek(fileno(f), (off_t)sizeof *message, 0);
-	if (read(fileno(f), (char *) message, size) != size)
+	size -= sizeof(struct message);
+	(void)fflush(f);
+	(void)lseek(fileno(f), (off_t)sizeof(*message), 0);
+	if (read(fileno(f), (char *)message, size) != size)
 		errx(1, "Message temporary file corrupted");
 	message[msgCount].m_size = 0;
 	message[msgCount].m_lines = 0;
-	Fclose(f);
+	(void)Fclose(f);
 }
 
 /*
@@ -240,7 +242,7 @@ append(mp, f)
 	struct message *mp;
 	FILE *f;
 {
-	return fwrite((char *) mp, sizeof *mp, 1, f) != 1;
+	return (fwrite((char *)mp, sizeof(*mp), 1, f) != 1);
 }
 
 /*
@@ -253,12 +255,12 @@ rm(name)
 	struct stat sb;
 
 	if (stat(name, &sb) < 0)
-		return(-1);
+		return (-1);
 	if (!S_ISREG(sb.st_mode)) {
 		errno = EISDIR;
-		return(-1);
+		return (-1);
 	}
-	return(unlink(name));
+	return (unlink(name));
 }
 
 static int sigdepth;		/* depth of holdsigs() */
@@ -282,7 +284,7 @@ relsesigs()
 {
 
 	if (--sigdepth == 0)
-		sigsetmask(omask);
+		(void)sigsetmask(omask);
 }
 
 /*
@@ -296,8 +298,8 @@ fsize(iob)
 	struct stat sbuf;
 
 	if (fstat(fileno(iob), &sbuf) < 0)
-		return 0;
-	return sbuf.st_size;
+		return (0);
+	return (sbuf.st_size);
 }
 
 /*
@@ -313,15 +315,14 @@ fsize(iob)
  */
 char *
 expand(name)
-	register char *name;
+	char *name;
 {
 	char xname[PATHSIZE];
 	char cmdbuf[PATHSIZE];		/* also used for file names */
-	register int pid, l;
-	register char *cp, *shell;
+	int pid, l;
+	char *cp, *sh;
 	int pivec[2];
 	struct stat sbuf;
-	extern int wait_status;
 
 	/*
 	 * The order of evaluation is "%" and "#" expand into constants.
@@ -332,63 +333,64 @@ expand(name)
 	switch (*name) {
 	case '%':
 		findmail(name[1] ? name + 1 : myname, xname, sizeof(xname));
-		return savestr(xname);
+		return (savestr(xname));
 	case '#':
 		if (name[1] != 0)
 			break;
 		if (prevfile[0] == 0) {
 			printf("No previous file\n");
-			return NOSTR;
+			return (NULL);
 		}
-		return savestr(prevfile);
+		return (savestr(prevfile));
 	case '&':
-		if (name[1] == 0 && (name = value("MBOX")) == NOSTR)
+		if (name[1] == 0 && (name = value("MBOX")) == NULL)
 			name = "~/mbox";
 		/* fall through */
 	}
 	if (name[0] == '+' && getfold(cmdbuf, sizeof(cmdbuf)) >= 0) {
-		snprintf(xname, sizeof(xname), "%s/%s", cmdbuf, name + 1);
+		(void)snprintf(xname, sizeof(xname), "%s/%s", cmdbuf, name + 1);
 		name = savestr(xname);
 	}
 	/* catch the most common shell meta character */
 	if (name[0] == '~' && homedir != NULL &&
 	    (name[1] == '/' || name[1] == '\0')) {
-		snprintf(xname, sizeof(xname), "%s%s", homedir, name + 1);
+		(void)snprintf(xname, sizeof(xname), "%s%s", homedir, name + 1);
 		name = savestr(xname);
 	}
 	if (!strpbrk(name, "~{[*?$`'\"\\"))
-		return name;
+		return (name);
 	if (pipe(pivec) < 0) {
 		warn("pipe");
-		return name;
+		return (name);
 	}
-	snprintf(cmdbuf, sizeof(cmdbuf), "echo %s", name);
-	if ((shell = value("SHELL")) == NOSTR)
-		shell = _PATH_CSHELL;
-	pid = start_command(shell, 0, -1, pivec[1], "-c", cmdbuf, NOSTR);
+	(void)snprintf(cmdbuf, sizeof(cmdbuf), "echo %s", name);
+	if ((sh = value("SHELL")) == NULL)
+		sh = _PATH_CSHELL;
+	pid = start_command(sh, 0, -1, pivec[1], "-c", cmdbuf, NULL);
 	if (pid < 0) {
-		close(pivec[0]);
-		close(pivec[1]);
-		return NOSTR;
+		(void)close(pivec[0]);
+		(void)close(pivec[1]);
+		return (NULL);
 	}
-	close(pivec[1]);
+	(void)close(pivec[1]);
 	l = read(pivec[0], xname, BUFSIZ);
-	close(pivec[0]);
-	if (wait_child(pid) < 0 && WIFSIGNALED(wait_status) && WTERMSIG(wait_status) != SIGPIPE) {
+	(void)close(pivec[0]);
+	if (wait_child(pid) < 0 && WIFSIGNALED(wait_status) &&
+	    WTERMSIG(wait_status) != SIGPIPE) {
 		fprintf(stderr, "\"%s\": Expansion failed.\n", name);
-		return NOSTR;
+		return (NULL);
 	}
 	if (l < 0) {
 		warn("read");
-		return NOSTR;
+		return (NULL);
 	}
 	if (l == 0) {
 		fprintf(stderr, "\"%s\": No match.\n", name);
-		return NOSTR;
+		return (NULL);
 	}
 	if (l == BUFSIZ) {
 		fprintf(stderr, "\"%s\": Expansion buffer overflow.\n", name);
-		return NOSTR;
+		return (NULL);
 	}
 	xname[l] = '\0';
 	for (cp = &xname[l-1]; *cp == '\n' && cp > xname; cp--)
@@ -396,9 +398,9 @@ expand(name)
 	cp[1] = '\0';
 	if (strchr(xname, ' ') && stat(xname, &sbuf) < 0) {
 		fprintf(stderr, "\"%s\": Ambiguous.\n", name);
-		return NOSTR;
+		return (NULL);
 	}
-	return savestr(xname);
+	return (savestr(xname));
 }
 
 /*
@@ -412,13 +414,14 @@ getfold(name, namelen)
 	char *folder;
 	int copylen;
 
-	if ((folder = value("folder")) == NOSTR)
+	if ((folder = value("folder")) == NULL)
 		return (-1);
 	if (*folder == '/')
 		copylen = strlcpy(name, folder, namelen);
 	else
-		copylen = snprintf(name, namelen, "%s/%s", homedir ? homedir : ".", folder);
-	return copylen >= namelen ? (-1) : (0);
+		copylen = snprintf(name, namelen, "%s/%s",
+		    homedir ? homedir : ".", folder);
+	return (copylen >= namelen ? (-1) : (0));
 }
 
 /*
@@ -427,15 +430,15 @@ getfold(name, namelen)
 char *
 getdeadletter()
 {
-	register char *cp;
+	char *cp;
 
-	if ((cp = value("DEAD")) == NOSTR || (cp = expand(cp)) == NOSTR)
+	if ((cp = value("DEAD")) == NULL || (cp = expand(cp)) == NULL)
 		cp = expand("~/dead.letter");
 	else if (*cp != '/') {
 		char buf[PATHSIZE];
 
-		(void) snprintf(buf, sizeof(buf), "~/%s", cp);
+		(void)snprintf(buf, sizeof(buf), "~/%s", cp);
 		cp = expand(buf);
 	}
-	return cp;
+	return (cp);
 }
diff --git a/usr.bin/mail/getname.c b/usr.bin/mail/getname.c
index dc812d5..4062e93 100644
--- a/usr.bin/mail/getname.c
+++ b/usr.bin/mail/getname.c
@@ -46,8 +46,7 @@ static const char rcsid[] =
 /* Getname / getuserid for those with hashed passwd data base). */
 
 /*
- * Search the passwd file for a uid. Return name on success,
- * NOSTR on failure
+ * Search the passwd file for a uid. Return name on success, NULL on failure.
  */
 char *
 getname(uid)
@@ -56,8 +55,8 @@ getname(uid)
 	struct passwd *pw;
 
 	if ((pw = getpwuid(uid)) == NULL)
-		return NOSTR;
-	return pw->pw_name;
+		return (NULL);
+	return (pw->pw_name);
 }
 
 /*
@@ -71,6 +70,6 @@ getuserid(name)
 	struct passwd *pw;
 
 	if ((pw = getpwnam(name)) == NULL)
-		return -1;
-	return pw->pw_uid;
+		return (-1);
+	return (pw->pw_uid);
 }
diff --git a/usr.bin/mail/head.c b/usr.bin/mail/head.c
index 41b0e23..b3a3b71 100644
--- a/usr.bin/mail/head.c
+++ b/usr.bin/mail/head.c
@@ -63,7 +63,7 @@ ishead(linebuf)
 	if (strncmp(linebuf, "From ", 5))
 		return (0);
 	parse(linebuf, &hl, parbuf);
-	if (hl.l_from == NOSTR || hl.l_date == NOSTR) {
+	if (hl.l_from == NULL || hl.l_date == NULL) {
 		fail(linebuf, "No from or date field");
 		return (0);
 	}
@@ -80,11 +80,11 @@ ishead(linebuf)
 /*ARGSUSED*/
 void
 fail(linebuf, reason)
-	char linebuf[], reason[];
+	const char *linebuf, *reason;
 {
 
 	/*
-	if (value("debug") == NOSTR)
+	if (value("debug") == NULL)
 		return;
 	fprintf(stderr, "\"%s\"\nnot a header because %s\n", linebuf, reason);
 	*/
@@ -99,15 +99,14 @@ fail(linebuf, reason)
 void
 parse(line, hl, pbuf)
 	char line[], pbuf[];
-	register struct headline *hl;
+	struct headline *hl;
 {
-	register char *cp;
-	char *sp;
+	char *cp, *sp;
 	char word[LINESIZE];
 
-	hl->l_from = NOSTR;
-	hl->l_tty = NOSTR;
-	hl->l_date = NOSTR;
+	hl->l_from = NULL;
+	hl->l_tty = NULL;
+	hl->l_date = NULL;
 	cp = line;
 	sp = pbuf;
 	/*
@@ -115,13 +114,13 @@ parse(line, hl, pbuf)
 	 */
 	cp = nextword(cp, word);
 	cp = nextword(cp, word);
-	if (*word)
+	if (*word != '\0')
 		hl->l_from = copyin(word, &sp);
-	if (cp != NOSTR && cp[0] == 't' && cp[1] == 't' && cp[2] == 'y') {
+	if (cp != NULL && cp[0] == 't' && cp[1] == 't' && cp[2] == 'y') {
 		cp = nextword(cp, word);
 		hl->l_tty = copyin(word, &sp);
 	}
-	if (cp != NOSTR)
+	if (cp != NULL)
 		hl->l_date = copyin(cp, &sp);
 }
 
@@ -133,14 +132,13 @@ parse(line, hl, pbuf)
  */
 char *
 copyin(src, space)
-	register char *src;
+	char *src;
 	char **space;
 {
-	register char *cp;
-	char *top;
+	char *cp, *top;
 
 	top = cp = *space;
-	while (*cp++ = *src++)
+	while ((*cp++ = *src++) != '\0')
 		;
 	*space = cp;
 	return (top);
@@ -171,7 +169,7 @@ isdate(date)
 	char date[];
 {
 
-	return cmatch(date, ctype) || cmatch(date, tmztype);
+	return (cmatch(date, ctype) || cmatch(date, tmztype));
 }
 
 /*
@@ -180,65 +178,65 @@ isdate(date)
  */
 int
 cmatch(cp, tp)
-	register char *cp, *tp;
+	char *cp, *tp;
 {
 
-	while (*cp && *tp)
+	while (*cp != '\0' && *tp != '\0')
 		switch (*tp++) {
 		case 'a':
 			if (!islower(*cp++))
-				return 0;
+				return (0);
 			break;
 		case 'A':
 			if (!isupper(*cp++))
-				return 0;
+				return (0);
 			break;
 		case ' ':
 			if (*cp++ != ' ')
-				return 0;
+				return (0);
 			break;
 		case '0':
 			if (!isdigit(*cp++))
-				return 0;
+				return (0);
 			break;
 		case 'O':
 			if (*cp != ' ' && !isdigit(*cp))
-				return 0;
+				return (0);
 			cp++;
 			break;
 		case ':':
 			if (*cp++ != ':')
-				return 0;
+				return (0);
 			break;
 		case 'N':
 			if (*cp++ != '\n')
-				return 0;
+				return (0);
 			break;
 		}
-	if (*cp || *tp)
-		return 0;
+	if (*cp != '\0' || *tp != '\0')
+		return (0);
 	return (1);
 }
 
 /*
  * Collect a liberal (space, tab delimited) word into the word buffer
  * passed.  Also, return a pointer to the next word following that,
- * or NOSTR if none follow.
+ * or NULL if none follow.
  */
 char *
 nextword(wp, wbuf)
-	register char *wp, *wbuf;
+	char *wp, *wbuf;
 {
-	register c;
+	int c;
 
-	if (wp == NOSTR) {
-		*wbuf = 0;
-		return (NOSTR);
+	if (wp == NULL) {
+		*wbuf = '\0';
+		return (NULL);
 	}
-	while ((c = *wp++) && c != ' ' && c != '\t') {
+	while ((c = *wp++) != '\0' && c != ' ' && c != '\t') {
 		*wbuf++ = c;
 		if (c == '"') {
- 			while ((c = *wp++) && c != '"')
+ 			while ((c = *wp++) != '\0' && c != '"')
  				*wbuf++ = c;
  			if (c == '"')
  				*wbuf++ = c;
@@ -249,7 +247,7 @@ nextword(wp, wbuf)
 	*wbuf = '\0';
 	for (; c == ' ' || c == '\t'; c = *wp++)
 		;
-	if (c == 0)
-		return (NOSTR);
+	if (c == '\0')
+		return (NULL);
 	return (wp - 1);
 }
diff --git a/usr.bin/mail/lex.c b/usr.bin/mail/lex.c
index 6f89a69..5f1bb52 100644
--- a/usr.bin/mail/lex.c
+++ b/usr.bin/mail/lex.c
@@ -52,7 +52,10 @@ static const char rcsid[] =
  * Lexical processing of commands.
  */
 
-char	*prompt = "& ";
+const char	*prompt = "& ";
+
+extern const struct cmd cmdtab[];
+extern const char *version;	
 
 /*
  * Set up editing on the given file name.
@@ -72,24 +75,24 @@ setfile(name)
 	char tempname[PATHSIZE];
 	static int shudclob;
 
-	if ((name = expand(name)) == NOSTR)
-		return -1;
+	if ((name = expand(name)) == NULL)
+		return (-1);
 
 	if ((ibuf = Fopen(name, "r")) == NULL) {
 		if (!isedit && errno == ENOENT)
 			goto nomail;
 		warn("%s", name);
-		return(-1);
+		return (-1);
 	}
 
 	if (fstat(fileno(ibuf), &stb) < 0) {
 		warn("fstat");
-		Fclose(ibuf);
+		(void)Fclose(ibuf);
 		return (-1);
 	}
 
 	if (S_ISDIR(stb.st_mode) || !S_ISREG(stb.st_mode)) {
-		Fclose(ibuf);
+		(void)Fclose(ibuf);
 		errno = S_ISDIR(stb.st_mode) ? EISDIR : EINVAL;
 		warn("%s", name);
 		return (-1);
@@ -115,10 +118,10 @@ setfile(name)
 	if ((i = open(name, 1)) < 0)
 		readonly++;
 	else
-		close(i);
+		(void)close(i);
 	if (shudclob) {
-		fclose(itf);
-		fclose(otf);
+		(void)fclose(itf);
+		(void)fclose(otf);
 	}
 	shudclob = 1;
 	edit = isedit;
@@ -126,25 +129,26 @@ setfile(name)
 	if (name != mailname)
 		strlcpy(mailname, name, sizeof(mailname));
 	mailsize = fsize(ibuf);
-	snprintf(tempname, sizeof(tempname), "%s/mail.RxXXXXXXXXXX", tmpdir);
+	(void)snprintf(tempname, sizeof(tempname),
+	    "%s/mail.RxXXXXXXXXXX", tmpdir);
 	if ((fd = mkstemp(tempname)) == -1 || (otf = fdopen(fd, "w")) == NULL)
 		err(1, "%s", tempname);
-	(void) fcntl(fileno(otf), F_SETFD, 1);
+	(void)fcntl(fileno(otf), F_SETFD, 1);
 	if ((itf = fopen(tempname, "r")) == NULL)
 		err(1, "%s", tempname);
-	(void) fcntl(fileno(itf), F_SETFD, 1);
-	rm(tempname);
+	(void)fcntl(fileno(itf), F_SETFD, 1);
+	(void)rm(tempname);
 	setptr(ibuf);
 	setmsize(msgCount);
-	Fclose(ibuf);
+	(void)Fclose(ibuf);
 	relsesigs();
 	sawcom = 0;
 	if (!edit && msgCount == 0) {
 nomail:
 		fprintf(stderr, "No mail for %s\n", who);
-		return -1;
+		return (-1);
 	}
-	return(0);
+	return (0);
 }
 
 int	*msgvec;
@@ -157,19 +161,17 @@ int	reset_on_stop;			/* do a reset() if stopped */
 void
 commands()
 {
-	int eofloop = 0;
-	register int n;
+	int n, eofloop = 0;
 	char linebuf[LINESIZE];
-	void intr(), stop(), hangup();
 
 	if (!sourcing) {
 		if (signal(SIGINT, SIG_IGN) != SIG_IGN)
-			signal(SIGINT, intr);
+			(void)signal(SIGINT, intr);
 		if (signal(SIGHUP, SIG_IGN) != SIG_IGN)
-			signal(SIGHUP, hangup);
-		signal(SIGTSTP, stop);
-		signal(SIGTTOU, stop);
-		signal(SIGTTIN, stop);
+			(void)signal(SIGHUP, hangup);
+		(void)signal(SIGTSTP, stop);
+		(void)signal(SIGTTOU, stop);
+		(void)signal(SIGTTIN, stop);
 	}
 	setexit();
 	for (;;) {
@@ -177,11 +179,11 @@ commands()
 		 * Print the prompt, if needed.  Clear out
 		 * string space, and flush the output.
 		 */
-		if (!sourcing && value("interactive") != NOSTR) {
+		if (!sourcing && value("interactive") != NULL) {
 			reset_on_stop = 1;
 			printf("%s", prompt);
 		}
-		fflush(stdout);
+		(void)fflush(stdout);
 		sreset();
 		/*
 		 * Read a line of commands from the current input
@@ -210,8 +212,8 @@ commands()
 				unstack();
 				continue;
 			}
-			if (value("interactive") != NOSTR &&
-			    value("ignoreeof") != NOSTR &&
+			if (value("interactive") != NULL &&
+			    value("ignoreeof") != NULL &&
 			    ++eofloop < 25) {
 				printf("Use \"quit\" to quit.\n");
 				continue;
@@ -238,10 +240,9 @@ execute(linebuf, contxt)
 {
 	char word[LINESIZE];
 	char *arglist[MAXARGC];
-	struct cmd *com;
-	register char *cp, *cp2;
-	register int c;
-	int muvec[2];
+	const struct cmd *com;
+	char *cp, *cp2;
+	int c, muvec[2];
 	int e = 1;
 
 	/*
@@ -261,10 +262,10 @@ execute(linebuf, contxt)
 			goto out;
 		}
 		shell(cp+1);
-		return(0);
+		return (0);
 	}
 	cp2 = word;
-	while (*cp && strchr(" \t0123456789$^.:/-+*'\"", *cp) == NOSTR)
+	while (*cp != '\0' && strchr(" \t0123456789$^.:/-+*'\"", *cp) == NULL)
 		*cp2++ = *cp++;
 	*cp2 = '\0';
 
@@ -277,9 +278,9 @@ execute(linebuf, contxt)
 	 */
 
 	if (sourcing && *word == '\0')
-		return(0);
+		return (0);
 	com = lex(word);
-	if (com == NONE) {
+	if (com == NULL) {
 		printf("Unknown command: \"%s\"\n", word);
 		goto out;
 	}
@@ -290,8 +291,8 @@ execute(linebuf, contxt)
 	 */
 
 	if ((com->c_argtype & F) == 0)
-		if (cond == CRCV && !rcvmode || cond == CSEND && rcvmode)
-			return(0);
+		if ((cond == CRCV && !rcvmode) || (cond == CSEND && rcvmode))
+			return (0);
 
 	/*
 	 * Process the arguments to the command, depending
@@ -332,8 +333,7 @@ execute(linebuf, contxt)
 		if ((c = getmsglist(cp, msgvec, com->c_msgflag)) < 0)
 			break;
 		if (c  == 0) {
-			*msgvec = first(com->c_msgflag,
-				com->c_msgmask);
+			*msgvec = first(com->c_msgflag, com->c_msgmask);
 			msgvec[1] = 0;
 		}
 		if (*msgvec == 0) {
@@ -372,16 +372,16 @@ execute(linebuf, contxt)
 		 * A vector of strings, in shell style.
 		 */
 		if ((c = getrawlist(cp, arglist,
-				sizeof arglist / sizeof *arglist)) < 0)
+		    sizeof(arglist) / sizeof(*arglist))) < 0)
 			break;
 		if (c < com->c_minargs) {
 			printf("%s requires at least %d arg(s)\n",
-				com->c_name, com->c_minargs);
+			    com->c_name, com->c_minargs);
 			break;
 		}
 		if (c > com->c_maxargs) {
 			printf("%s takes no more than %d arg(s)\n",
-				com->c_name, com->c_maxargs);
+			    com->c_name, com->c_maxargs);
 			break;
 		}
 		e = (*com->c_func)(arglist);
@@ -406,14 +406,14 @@ out:
 	 */
 	if (e) {
 		if (e < 0)
-			return 1;
+			return (1);
 		if (loading)
-			return 1;
+			return (1);
 		if (sourcing)
 			unstack();
-		return 0;
+		return (0);
 	}
-	if (value("autoprint") != NOSTR && com->c_argtype & P)
+	if (value("autoprint") != NULL && com->c_argtype & P)
 		if ((dot->m_flag & MDELETED) == 0) {
 			muvec[0] = dot - &message[0] + 1;
 			muvec[1] = 0;
@@ -421,7 +421,7 @@ out:
 		}
 	if (!sourcing && (com->c_argtype & T) == 0)
 		sawcom = 1;
-	return(0);
+	return (0);
 }
 
 /*
@@ -434,8 +434,8 @@ setmsize(sz)
 {
 
 	if (msgvec != 0)
-		free((char *) msgvec);
-	msgvec = (int *) calloc((unsigned) (sz + 1), sizeof *msgvec);
+		(void)free(msgvec);
+	msgvec = calloc((unsigned)(sz + 1), sizeof(*msgvec));
 }
 
 /*
@@ -443,15 +443,14 @@ setmsize(sz)
  * to the passed command "word"
  */
 
-struct cmd *
+__const struct cmd *
 lex(word)
 	char word[];
 {
-	register struct cmd *cp;
-	extern struct cmd cmdtab[];
+	const struct cmd *cp;
 
 	/*
-	 * ignore trailing chars after `#' 
+	 * ignore trailing chars after `#'
 	 *
 	 * lines with beginning `#' are comments
 	 * spaces before `#' are ignored in execute()
@@ -461,10 +460,10 @@ lex(word)
 	    *(word+1) = '\0';
 
 
-	for (cp = &cmdtab[0]; cp->c_name != NOSTR; cp++)
+	for (cp = &cmdtab[0]; cp->c_name != NULL; cp++)
 		if (isprefix(word, cp->c_name))
-			return(cp);
-	return(NONE);
+			return (cp);
+	return (NULL);
 }
 
 /*
@@ -473,16 +472,16 @@ lex(word)
  */
 int
 isprefix(as1, as2)
-	char *as1, *as2;
+	const char *as1, *as2;
 {
-	register char *s1, *s2;
+	const char *s1, *s2;
 
 	s1 = as1;
 	s2 = as2;
 	while (*s1++ == *s2)
 		if (*s2++ == '\0')
-			return(1);
-	return(*--s1 == '\0');
+			return (1);
+	return (*--s1 == '\0');
 }
 
 /*
@@ -511,7 +510,7 @@ intr(s)
 	close_all_files();
 
 	if (image >= 0) {
-		close(image);
+		(void)close(image);
 		image = -1;
 	}
 	fprintf(stderr, "Interrupt\n");
@@ -527,10 +526,10 @@ stop(s)
 {
 	sig_t old_action = signal(s, SIG_DFL);
 
-	sigsetmask(sigblock(0) & ~sigmask(s));
-	kill(0, s);
-	sigblock(sigmask(s));
-	signal(s, old_action);
+	(void)sigsetmask(sigblock(0) & ~sigmask(s));
+	(void)kill(0, s);
+	(void)sigblock(sigmask(s));
+	(void)signal(s, old_action);
 	if (reset_on_stop) {
 		reset_on_stop = 0;
 		reset(0);
@@ -563,7 +562,7 @@ announce()
 	vec[0] = mdot;
 	vec[1] = 0;
 	dot = &message[mdot - 1];
-	if (msgCount > 0 && value("noheader") == NOSTR) {
+	if (msgCount > 0 && value("noheader") == NULL) {
 		inithdr++;
 		headers(vec);
 		inithdr = 0;
@@ -577,8 +576,8 @@ announce()
 int
 newfileinfo()
 {
-	register struct message *mp;
-	register int u, n, mdot, d, s;
+	struct message *mp;
+	int u, n, mdot, d, s;
 	char fname[PATHSIZE+1], zname[PATHSIZE+1], *ename;
 
 	for (mp = &message[0]; mp < &message[msgCount]; mp++)
@@ -607,7 +606,8 @@ newfileinfo()
 	if (getfold(fname, sizeof(fname) - 1) >= 0) {
 		strcat(fname, "/");
 		if (strncmp(fname, mailname, strlen(fname)) == 0) {
-			snprintf(zname, sizeof(zname), "+%s", mailname + strlen(fname));
+			(void)snprintf(zname, sizeof(zname), "+%s",
+			    mailname + strlen(fname));
 			ename = zname;
 		}
 	}
@@ -627,7 +627,7 @@ newfileinfo()
 	if (readonly)
 		printf(" [Read only]");
 	printf("\n");
-	return(mdot);
+	return (mdot);
 }
 
 /*
@@ -639,10 +639,9 @@ int
 pversion(e)
 	int e;
 {
-	extern char *version;
 
 	printf("Version %s\n", version);
-	return(0);
+	return (0);
 }
 
 /*
@@ -652,7 +651,7 @@ void
 load(name)
 	char *name;
 {
-	register FILE *in, *oldin;
+	FILE *in, *oldin;
 
 	if ((in = Fopen(name, "r")) == NULL)
 		return;
@@ -664,5 +663,5 @@ load(name)
 	loading = 0;
 	sourcing = 0;
 	input = oldin;
-	Fclose(in);
+	(void)Fclose(in);
 }
diff --git a/usr.bin/mail/list.c b/usr.bin/mail/list.c
index d5bd968..04b1586 100644
--- a/usr.bin/mail/list.c
+++ b/usr.bin/mail/list.c
@@ -60,21 +60,21 @@ getmsglist(buf, vector, flags)
 	char *buf;
 	int *vector, flags;
 {
-	register int *ip;
-	register struct message *mp;
+	int *ip;
+	struct message *mp;
 
 	if (msgCount == 0) {
 		*vector = 0;
-		return 0;
+		return (0);
 	}
 	if (markall(buf, flags) < 0)
-		return(-1);
+		return (-1);
 	ip = vector;
 	for (mp = &message[0]; mp < &message[msgCount]; mp++)
 		if (mp->m_flag & MMARK)
 			*ip++ = mp - &message[0] + 1;
 	*ip = 0;
-	return(ip - vector);
+	return (ip - vector);
 }
 
 /*
@@ -104,12 +104,12 @@ struct coltab {
 	int	co_mask;		/* m_status bits to mask */
 	int	co_equal;		/* ... must equal this */
 } coltab[] = {
-	'n',		CMNEW,		MNEW,		MNEW,
-	'o',		CMOLD,		MNEW,		0,
-	'u',		CMUNREAD,	MREAD,		0,
-	'd',		CMDELETED,	MDELETED,	MDELETED,
-	'r',		CMREAD,		MREAD,		MREAD,
-	0,		0,		0,		0
+	{ 'n',		CMNEW,		MNEW,		MNEW	},
+	{ 'o',		CMOLD,		MNEW,		0	},
+	{ 'u',		CMUNREAD,	MREAD,		0	},
+	{ 'd',		CMDELETED,	MDELETED,	MDELETED},
+	{ 'r',		CMREAD,		MREAD,		MREAD	},
+	{ 0,		0,		0,		0	}
 };
 
 static	int	lastcolmod;
@@ -119,9 +119,9 @@ markall(buf, f)
 	char buf[];
 	int f;
 {
-	register char **np;
-	register int i;
-	register struct message *mp;
+	char **np;
+	int i;
+	struct message *mp;
 	char *namelist[NMLSIZE], *bufp;
 	int tok, beg, mc, star, other, valdot, colmod, colresult;
 
@@ -143,13 +143,13 @@ markall(buf, f)
 number:
 			if (star) {
 				printf("No numbers mixed with *\n");
-				return(-1);
+				return (-1);
 			}
 			mc++;
 			other++;
 			if (beg != 0) {
 				if (check(lexnumber, f))
-					return(-1);
+					return (-1);
 				for (i = beg; i <= lexnumber; i++)
 					if (f == MDELETED || (message[i - 1].m_flag & MDELETED) == 0)
 						mark(i);
@@ -158,7 +158,7 @@ number:
 			}
 			beg = lexnumber;
 			if (check(beg, f))
-				return(-1);
+				return (-1);
 			tok = scan(&bufp);
 			regret(tok);
 			if (tok != TDASH) {
@@ -170,14 +170,14 @@ number:
 		case TPLUS:
 			if (beg != 0) {
 				printf("Non-numeric second argument\n");
-				return(-1);
+				return (-1);
 			}
 			i = valdot;
 			do {
 				i++;
 				if (i > msgCount) {
 					printf("Referencing beyond EOF\n");
-					return(-1);
+					return (-1);
 				}
 			} while ((message[i - 1].m_flag & MDELETED) != f);
 			mark(i);
@@ -190,7 +190,7 @@ number:
 					i--;
 					if (i <= 0) {
 						printf("Referencing before 1\n");
-						return(-1);
+						return (-1);
 					}
 				} while ((message[i - 1].m_flag & MDELETED) != f);
 				mark(i);
@@ -200,7 +200,7 @@ number:
 		case TSTRING:
 			if (beg != 0) {
 				printf("Non-numeric second argument\n");
-				return(-1);
+				return (-1);
 			}
 			other++;
 			if (lexstring[0] == ':') {
@@ -208,7 +208,7 @@ number:
 				if (colresult == 0) {
 					printf("Unknown colon modifier \"%s\"\n",
 					    lexstring);
-					return(-1);
+					return (-1);
 				}
 				colmod |= colresult;
 			}
@@ -221,24 +221,24 @@ number:
 		case TDOT:
 			lexnumber = metamess(lexstring[0], f);
 			if (lexnumber == -1)
-				return(-1);
+				return (-1);
 			goto number;
 
 		case TSTAR:
 			if (other) {
 				printf("Can't mix \"*\" with anything\n");
-				return(-1);
+				return (-1);
 			}
 			star++;
 			break;
 
 		case TERROR:
-			return -1;
+			return (-1);
 		}
 		tok = scan(&bufp);
 	}
 	lastcolmod = colmod;
-	*np = NOSTR;
+	*np = NULL;
 	mc = 0;
 	if (star) {
 		for (i = 0; i < msgCount; i++)
@@ -248,9 +248,9 @@ number:
 			}
 		if (mc == 0) {
 			printf("No applicable messages.\n");
-			return(-1);
+			return (-1);
 		}
-		return(0);
+		return (0);
 	}
 
 	/*
@@ -271,7 +271,7 @@ number:
 
 	if (np > namelist) {
 		for (i = 1; i <= msgCount; i++) {
-			for (mc = 0, np = &namelist[0]; *np != NOSTR; np++)
+			for (mc = 0, np = &namelist[0]; *np != NULL; np++)
 				if (**np == '/') {
 					if (matchsubj(*np, i)) {
 						mc++;
@@ -301,10 +301,10 @@ number:
 		if (mc == 0) {
 			printf("No applicable messages from {%s",
 				namelist[0]);
-			for (np = &namelist[1]; *np != NOSTR; np++)
+			for (np = &namelist[1]; *np != NULL; np++)
 				printf(", %s", *np);
 			printf("}\n");
-			return(-1);
+			return (-1);
 		}
 	}
 
@@ -315,10 +315,10 @@ number:
 
 	if (colmod != 0) {
 		for (i = 1; i <= msgCount; i++) {
-			register struct coltab *colp;
+			struct coltab *colp;
 
 			mp = &message[i - 1];
-			for (colp = &coltab[0]; colp->co_char; colp++)
+			for (colp = &coltab[0]; colp->co_char != '\0'; colp++)
 				if (colp->co_bit & colmod)
 					if ((mp->m_flag & colp->co_mask)
 					    != colp->co_equal)
@@ -329,17 +329,17 @@ number:
 			if (mp->m_flag & MMARK)
 				break;
 		if (mp >= &message[msgCount]) {
-			register struct coltab *colp;
+			struct coltab *colp;
 
 			printf("No messages satisfy");
-			for (colp = &coltab[0]; colp->co_char; colp++)
+			for (colp = &coltab[0]; colp->co_char != '\0'; colp++)
 				if (colp->co_bit & colmod)
 					printf(" :%c", colp->co_char);
 			printf("\n");
-			return(-1);
+			return (-1);
 		}
 	}
-	return(0);
+	return (0);
 }
 
 /*
@@ -350,14 +350,14 @@ int
 evalcol(col)
 	int col;
 {
-	register struct coltab *colp;
+	struct coltab *colp;
 
 	if (col == 0)
-		return(lastcolmod);
-	for (colp = &coltab[0]; colp->co_char; colp++)
+		return (lastcolmod);
+	for (colp = &coltab[0]; colp->co_char != '\0'; colp++)
 		if (colp->co_char == col)
-			return(colp->co_bit);
-	return(0);
+			return (colp->co_bit);
+	return (0);
 }
 
 /*
@@ -369,18 +369,18 @@ int
 check(mesg, f)
 	int mesg, f;
 {
-	register struct message *mp;
+	struct message *mp;
 
 	if (mesg < 1 || mesg > msgCount) {
 		printf("%d: Invalid message number\n", mesg);
-		return(-1);
+		return (-1);
 	}
 	mp = &message[mesg-1];
 	if (f != MDELETED && (mp->m_flag & MDELETED) != 0) {
 		printf("%d: Inappropriate message\n", mesg);
-		return(-1);
+		return (-1);
 	}
-	return(0);
+	return (0);
 }
 
 /*
@@ -393,12 +393,12 @@ getrawlist(line, argv, argc)
 	char **argv;
 	int  argc;
 {
-	register char c, *cp, *cp2, quotec;
+	char c, *cp, *cp2, quotec;
 	int argn;
 	char *linebuf;
 	size_t linebufsize = BUFSIZ;
 
-	if ((linebuf = (char *)malloc(linebufsize)) == NULL)
+	if ((linebuf = malloc(linebufsize)) == NULL)
 		err(1, "Out of memory");
 
 	argn = 0;
@@ -468,8 +468,8 @@ getrawlist(line, argv, argc)
 					if (c == '?')
 						*cp2++ = '\177';
 					/* null doesn't show up anyway */
-					else if (c >= 'A' && c <= '_' ||
-						 c >= 'a' && c <= 'z')
+					else if ((c >= 'A' && c <= '_') ||
+					    (c >= 'a' && c <= 'z'))
 						*cp2++ = c & 037;
 					else {
 						*cp2++ = '^';
@@ -487,9 +487,9 @@ getrawlist(line, argv, argc)
 		*cp2 = '\0';
 		argv[argn++] = savestr(linebuf);
 	}
-	argv[argn] = NOSTR;
-	free(linebuf);
-	return argn;
+	argv[argn] = NULL;
+	(void)free(linebuf);
+	return (argn);
 }
 
 /*
@@ -503,30 +503,30 @@ struct lex {
 	char	l_char;
 	char	l_token;
 } singles[] = {
-	'$',	TDOLLAR,
-	'.',	TDOT,
-	'^',	TUP,
-	'*',	TSTAR,
-	'-',	TDASH,
-	'+',	TPLUS,
-	'(',	TOPEN,
-	')',	TCLOSE,
-	0,	0
+	{ '$',	TDOLLAR	},
+	{ '.',	TDOT	},
+	{ '^',	TUP 	},
+	{ '*',	TSTAR 	},
+	{ '-',	TDASH 	},
+	{ '+',	TPLUS 	},
+	{ '(',	TOPEN 	},
+	{ ')',	TCLOSE 	},
+	{ 0,	0 	}
 };
 
 int
 scan(sp)
 	char **sp;
 {
-	register char *cp, *cp2;
-	register int c;
-	register struct lex *lp;
+	char *cp, *cp2;
+	int c;
+	struct lex *lp;
 	int quotec;
 
 	if (regretp >= 0) {
 		strcpy(lexstring, string_stack[regretp]);
 		lexnumber = numberstack[regretp];
-		return(regretstack[regretp--]);
+		return (regretstack[regretp--]);
 	}
 	cp = *sp;
 	cp2 = lexstring;
@@ -546,7 +546,7 @@ scan(sp)
 
 	if (c == '\0') {
 		*sp = --cp;
-		return(TEOL);
+		return (TEOL);
 	}
 
 	/*
@@ -564,7 +564,7 @@ scan(sp)
 		}
 		*cp2 = '\0';
 		*sp = --cp;
-		return(TNUMBER);
+		return (TNUMBER);
 	}
 
 	/*
@@ -572,12 +572,12 @@ scan(sp)
 	 * if found.
 	 */
 
-	for (lp = &singles[0]; lp->l_char != 0; lp++)
+	for (lp = &singles[0]; lp->l_char != '\0'; lp++)
 		if (c == lp->l_char) {
 			lexstring[0] = c;
 			lexstring[1] = '\0';
 			*sp = cp;
-			return(lp->l_token);
+			return (lp->l_token);
 		}
 
 	/*
@@ -604,13 +604,13 @@ scan(sp)
 			*cp2++ = c;
 		c = *cp++;
 	}
-	if (quotec && c == 0) {
+	if (quotec && c == '\0') {
 		fprintf(stderr, "Missing %c\n", quotec);
-		return TERROR;
+		return (TERROR);
 	}
 	*sp = --cp;
 	*cp2 = '\0';
-	return(TSTRING);
+	return (TSTRING);
 }
 
 /*
@@ -645,19 +645,19 @@ int
 first(f, m)
 	int f, m;
 {
-	register struct message *mp;
+	struct message *mp;
 
 	if (msgCount == 0)
-		return 0;
+		return (0);
 	f &= MDELETED;
 	m &= MDELETED;
 	for (mp = dot; mp < &message[msgCount]; mp++)
 		if ((mp->m_flag & m) == f)
-			return mp - message + 1;
+			return (mp - message + 1);
 	for (mp = dot-1; mp >= &message[0]; mp--)
 		if ((mp->m_flag & m) == f)
-			return mp - message + 1;
-	return 0;
+			return (mp - message + 1);
+	return (0);
 }
 
 /*
@@ -669,21 +669,21 @@ matchsender(str, mesg)
 	char *str;
 	int mesg;
 {
-	register char *cp, *cp2, *backup;
+	char *cp, *cp2, *backup;
 
-	if (!*str)	/* null string matches nothing instead of everything */
-		return 0;
+	if (*str == '\0')	/* null string matches nothing instead of everything */
+		return (0);
 	backup = cp2 = nameof(&message[mesg - 1], 0);
 	cp = str;
-	while (*cp2) {
-		if (*cp == 0)
-			return(1);
+	while (*cp2 != '\0') {
+		if (*cp == '\0')
+			return (1);
 		if (toupper(*cp++) != toupper(*cp2++)) {
 			cp2 = ++backup;
 			cp = str;
 		}
 	}
-	return(*cp == 0);
+	return (*cp == '\0');
 }
 
 /*
@@ -700,8 +700,8 @@ matchsubj(str, mesg)
 	char *str;
 	int mesg;
 {
-	register struct message *mp;
-	register char *cp, *cp2, *backup;
+	struct message *mp;
+	char *cp, *cp2, *backup;
 
 	str++;
 	if (*str == '\0')
@@ -714,7 +714,7 @@ matchsubj(str, mesg)
 	 * Now look, ignoring case, for the word in the string.
 	 */
 
-	if (value("searchheaders") && (cp = strchr(str, ':'))) {
+	if (value("searchheaders") && (cp = strchr(str, ':')) != NULL) {
 		*cp++ = '\0';
 		cp2 = hfield(str, mp);
 		cp[-1] = ':';
@@ -723,18 +723,18 @@ matchsubj(str, mesg)
 		cp = str;
 		cp2 = hfield("subject", mp);
 	}
-	if (cp2 == NOSTR)
-		return(0);
+	if (cp2 == NULL)
+		return (0);
 	backup = cp2;
-	while (*cp2) {
-		if (*cp == 0)
-			return(1);
+	while (*cp2 != '\0') {
+		if (*cp == '\0')
+			return (1);
 		if (toupper(*cp++) != toupper(*cp2++)) {
 			cp2 = ++backup;
 			cp = str;
 		}
 	}
-	return(*cp == 0);
+	return (*cp == 0);
 }
 
 /*
@@ -744,7 +744,7 @@ void
 mark(mesg)
 	int mesg;
 {
-	register int i;
+	int i;
 
 	i = mesg;
 	if (i < 1 || i > msgCount)
@@ -759,7 +759,7 @@ void
 unmark(mesg)
 	int mesg;
 {
-	register int i;
+	int i;
 
 	i = mesg;
 	if (i < 1 || i > msgCount)
@@ -774,8 +774,8 @@ int
 metamess(meta, f)
 	int meta, f;
 {
-	register int c, m;
-	register struct message *mp;
+	int c, m;
+	struct message *mp;
 
 	c = meta;
 	switch (c) {
@@ -785,9 +785,9 @@ metamess(meta, f)
 		 */
 		for (mp = &message[0]; mp < &message[msgCount]; mp++)
 			if ((mp->m_flag & MDELETED) == f)
-				return(mp - &message[0] + 1);
+				return (mp - &message[0] + 1);
 		printf("No applicable messages\n");
-		return(-1);
+		return (-1);
 
 	case '$':
 		/*
@@ -795,9 +795,9 @@ metamess(meta, f)
 		 */
 		for (mp = &message[msgCount-1]; mp >= &message[0]; mp--)
 			if ((mp->m_flag & MDELETED) == f)
-				return(mp - &message[0] + 1);
+				return (mp - &message[0] + 1);
 		printf("No applicable messages\n");
-		return(-1);
+		return (-1);
 
 	case '.':
 		/*
@@ -806,12 +806,12 @@ metamess(meta, f)
 		m = dot - &message[0] + 1;
 		if ((dot->m_flag & MDELETED) != f) {
 			printf("%d: Inappropriate message\n", m);
-			return(-1);
+			return (-1);
 		}
-		return(m);
+		return (m);
 
 	default:
 		printf("Unknown metachar (%c)\n", c);
-		return(-1);
+		return (-1);
 	}
 }
diff --git a/usr.bin/mail/main.c b/usr.bin/mail/main.c
index 97617ee..633febc 100644
--- a/usr.bin/mail/main.c
+++ b/usr.bin/mail/main.c
@@ -57,26 +57,26 @@ static const char rcsid[] =
 
 jmp_buf	hdrjmp;
 
+extern const char *version;
+
 int
 main(argc, argv)
 	int argc;
 	char *argv[];
 {
-	register int i;
+	int i;
 	struct name *to, *cc, *bcc, *smopts;
 	char *subject, *replyto;
 	char *ef, *cp;
 	char nosrc = 0;
-	void hdrstop();
 	sig_t prevint;
-	void sigchild();
 
 	/*
 	 * Set up a reasonable environment.
 	 * Figure out whether we are being run interactively,
 	 * start the SIGCHLD catcher, and so forth.
 	 */
-	(void) signal(SIGCHLD, sigchild);
+	(void)signal(SIGCHLD, sigchild);
 	if (isatty(0))
 		assign("interactive", "");
 	image = -1;
@@ -87,13 +87,13 @@ main(argc, argv)
 	 * of users to mail to.  Argp will be set to point to the
 	 * first of these users.
 	 */
-	ef = NOSTR;
-	to = NIL;
-	cc = NIL;
-	bcc = NIL;
-	smopts = NIL;
-	subject = NOSTR;
-	replyto = NOSTR;
+	ef = NULL;
+	to = NULL;
+	cc = NULL;
+	bcc = NULL;
+	smopts = NULL;
+	subject = NULL;
+	replyto = NULL;
 	while ((i = getopt(argc, argv, "INT:b:c:dfins:u:v")) != -1) {
 		switch (i) {
 		case 'T':
@@ -103,16 +103,16 @@ main(argc, argv)
 			 */
 			Tflag = optarg;
 			if ((i = open(Tflag, O_CREAT | O_TRUNC | O_WRONLY,
-				      0600)) < 0)
+			    0600)) < 0)
 				err(1, "%s", Tflag);
-			close(i);
+			(void)close(i);
 			break;
 		case 'u':
 			/*
 			 * Next argument is person to pretend to be.
 			 */
 			myname = optarg;
-                        unsetenv("MAIL");
+			unsetenv("MAIL");
 			break;
 		case 'i':
 			/*
@@ -141,7 +141,7 @@ main(argc, argv)
 			 * getopt() can't handle optional arguments, so here
 			 * is an ugly hack to get around it.
 			 */
-			if ((argv[optind]) && (argv[optind][0] != '-'))
+			if ((argv[optind] != NULL) && (argv[optind][0] != '-'))
 				ef = argv[optind++];
 			else
 				ef = "&";
@@ -192,16 +192,16 @@ Usage: %s [-iInv] [-s subject] [-c cc-addr] [-b bcc-addr] to-addr ...\n\
 			exit(1);
 		}
 	}
-	for (i = optind; (argv[i]) && (*argv[i] != '-'); i++)
+	for (i = optind; (argv[i] != NULL) && (*argv[i] != '-'); i++)
 		to = cat(to, nalloc(argv[i], GTO));
-	for (; argv[i]; i++)
+	for (; argv[i] != NULL; i++)
 		smopts = cat(smopts, nalloc(argv[i], 0));
 	/*
 	 * Check for inconsistent arguments.
 	 */
-	if (to == NIL && (subject != NOSTR || cc != NIL || bcc != NIL))
+	if (to == NULL && (subject != NULL || cc != NULL || bcc != NULL))
 		errx(1, "You must specify direct recipients with -s, -c, or -b.");
-	if (ef != NOSTR && to != NIL)
+	if (ef != NULL && to != NULL)
 		errx(1, "Cannot give -f and people to send to.");
 	tinit();
 	setscreensize();
@@ -239,26 +239,24 @@ Usage: %s [-iInv] [-s subject] [-c cc-addr] [-b bcc-addr] to-addr ...\n\
 	 * Decide whether we are editing a mailbox or reading
 	 * the system mailbox, and open up the right stuff.
 	 */
-	if (ef == NOSTR)
+	if (ef == NULL)
 		ef = "%";
 	if (setfile(ef) < 0)
 		exit(1);		/* error already reported */
 	if (setjmp(hdrjmp) == 0) {
-		extern char *version;
-
 		if ((prevint = signal(SIGINT, SIG_IGN)) != SIG_IGN)
-			signal(SIGINT, hdrstop);
-		if (value("quiet") == NOSTR)
+			(void)signal(SIGINT, hdrstop);
+		if (value("quiet") == NULL)
 			printf("Mail version %s.  Type ? for help.\n",
 				version);
 		announce();
-		fflush(stdout);
-		signal(SIGINT, prevint);
+		(void)fflush(stdout);
+		(void)signal(SIGINT, prevint);
 	}
 	commands();
-	signal(SIGHUP, SIG_IGN);
-	signal(SIGINT, SIG_IGN);
-	signal(SIGQUIT, SIG_IGN);
+	(void)signal(SIGHUP, SIG_IGN);
+	(void)signal(SIGINT, SIG_IGN);
+	(void)signal(SIGQUIT, SIG_IGN);
 	quit();
 	exit(0);
 }
@@ -266,12 +264,13 @@ Usage: %s [-iInv] [-s subject] [-c cc-addr] [-b bcc-addr] to-addr ...\n\
 /*
  * Interrupt printing of the headers.
  */
+/*ARGSUSED*/
 void
 hdrstop(signo)
 	int signo;
 {
 
-	fflush(stdout);
+	(void)fflush(stdout);
 	fprintf(stderr, "\nInterrupt\n");
 	longjmp(hdrjmp, 1);
 }
@@ -291,7 +290,7 @@ setscreensize()
 	struct termios tio;
 	speed_t speed = 0;
 
-	if (ioctl(1, TIOCGWINSZ, (char *) &ws) < 0)
+	if (ioctl(1, TIOCGWINSZ, (char *)&ws) < 0)
 		ws.ws_col = ws.ws_row = 0;
 	if (tcgetattr(1, &tio) != -1)
 		speed = cfgetospeed(&tio);
diff --git a/usr.bin/mail/names.c b/usr.bin/mail/names.c
index 1fca53c..8d4bb42 100644
--- a/usr.bin/mail/names.c
+++ b/usr.bin/mail/names.c
@@ -59,14 +59,14 @@ nalloc(str, ntype)
 	char str[];
 	int ntype;
 {
-	register struct name *np;
+	struct name *np;
 
-	np = (struct name *) salloc(sizeof *np);
-	np->n_flink = NIL;
-	np->n_blink = NIL;
+	np = (struct name *)salloc(sizeof(*np));
+	np->n_flink = NULL;
+	np->n_blink = NULL;
 	np->n_type = ntype;
 	np->n_name = savestr(str);
-	return(np);
+	return (np);
 }
 
 /*
@@ -76,48 +76,47 @@ struct name *
 tailof(name)
 	struct name *name;
 {
-	register struct name *np;
+	struct name *np;
 
 	np = name;
-	if (np == NIL)
-		return(NIL);
-	while (np->n_flink != NIL)
+	if (np == NULL)
+		return (NULL);
+	while (np->n_flink != NULL)
 		np = np->n_flink;
-	return(np);
+	return (np);
 }
 
 /*
  * Extract a list of names from a line,
  * and make a list of names from it.
- * Return the list or NIL if none found.
+ * Return the list or NULL if none found.
  */
 struct name *
 extract(line, ntype)
 	char line[];
 	int ntype;
 {
-	register char *cp;
-	register struct name *top, *np, *t;
-	char *nbuf;
+	char *cp, *nbuf;
+	struct name *top, *np, *t;
 
-	if (line == NOSTR || *line == '\0')
-		return NIL;
-	if ((nbuf = (char *)malloc(strlen(line) + 1)) == NULL)
+	if (line == NULL || *line == '\0')
+		return (NULL);
+	if ((nbuf = malloc(strlen(line) + 1)) == NULL)
 		err(1, "Out of memory");
-	top = NIL;
-	np = NIL;
+	top = NULL;
+	np = NULL;
 	cp = line;
-	while ((cp = yankword(cp, nbuf)) != NOSTR) {
+	while ((cp = yankword(cp, nbuf)) != NULL) {
 		t = nalloc(nbuf, ntype);
-		if (top == NIL)
+		if (top == NULL)
 			top = t;
 		else
 			np->n_flink = t;
 		t->n_blink = np;
 		np = t;
 	}
-	free(nbuf);
-	return top;
+	(void)free(nbuf);
+	return (top);
 }
 
 /*
@@ -125,22 +124,21 @@ extract(line, ntype)
  */
 char *
 detract(np, ntype)
-	register struct name *np;
+	struct name *np;
 	int ntype;
 {
-	register int s;
-	register char *cp, *top;
-	register struct name *p;
-	register int comma;
+	int s, comma;
+	char *cp, *top;
+	struct name *p;
 
 	comma = ntype & GCOMMA;
-	if (np == NIL)
-		return(NOSTR);
+	if (np == NULL)
+		return (NULL);
 	ntype &= ~GCOMMA;
 	s = 0;
 	if (debug && comma)
 		fprintf(stderr, "detract asked to insert commas\n");
-	for (p = np; p != NIL; p = p->n_flink) {
+	for (p = np; p != NULL; p = p->n_flink) {
 		if (ntype && (p->n_type & GMASK) != ntype)
 			continue;
 		s += strlen(p->n_name) + 1;
@@ -148,22 +146,22 @@ detract(np, ntype)
 			s++;
 	}
 	if (s == 0)
-		return(NOSTR);
+		return (NULL);
 	s += 2;
 	top = salloc(s);
 	cp = top;
-	for (p = np; p != NIL; p = p->n_flink) {
+	for (p = np; p != NULL; p = p->n_flink) {
 		if (ntype && (p->n_type & GMASK) != ntype)
 			continue;
 		cp += strlcpy(cp, p->n_name, strlen(p->n_name) + 1);
-		if (comma && p->n_flink != NIL)
+		if (comma && p->n_flink != NULL)
 			*cp++ = ',';
 		*cp++ = ' ';
 	}
 	*--cp = '\0';
 	if (comma && *--cp == ',')
 		*cp = '\0';
-	return(top);
+	return (top);
 }
 
 /*
@@ -174,14 +172,14 @@ char *
 yankword(ap, wbuf)
 	char *ap, wbuf[];
 {
-	register char *cp, *cp2;
+	char *cp, *cp2;
 
 	cp = ap;
 	for (;;) {
 		if (*cp == '\0')
-			return NOSTR;
+			return (NULL);
 		if (*cp == '(') {
-			register int nesting = 0;
+			int nesting = 0;
 
 			while (*cp != '\0') {
 				switch (*cp++) {
@@ -204,10 +202,11 @@ yankword(ap, wbuf)
 		for (cp2 = wbuf; *cp && (*cp2++ = *cp++) != '>';)
 			;
 	else
-		for (cp2 = wbuf; *cp && !strchr(" \t,(", *cp); *cp2++ = *cp++)
+		for (cp2 = wbuf; *cp != '\0' && strchr(" \t,(", *cp) == NULL;
+		    *cp2++ = *cp++)
 			;
 	*cp2 = '\0';
-	return cp;
+	return (cp);
 }
 
 /*
@@ -224,18 +223,17 @@ outof(names, fo, hp)
 	FILE *fo;
 	struct header *hp;
 {
-	register int c;
-	register struct name *np, *top;
-	time_t now, time();
-	char *date, *fname, *ctime();
+	int c, ispipe;
+	struct name *np, *top;
+	time_t now;
+	char *date, *fname;
 	FILE *fout, *fin;
-	int ispipe;
 
 	top = names;
 	np = names;
-	(void) time(&now);
+	(void)time(&now);
 	date = ctime(&now);
-	while (np != NIL) {
+	while (np != NULL) {
 		if (!isfileaddr(np->n_name) && np->n_name[0] != '|') {
 			np = np->n_flink;
 			continue;
@@ -255,8 +253,8 @@ outof(names, fo, hp)
 			int fd;
 			char tempname[PATHSIZE];
 
-			snprintf(tempname, sizeof(tempname),
-				 "%s/mail.ReXXXXXXXXXX", tmpdir);
+			(void)snprintf(tempname, sizeof(tempname),
+			    "%s/mail.ReXXXXXXXXXX", tmpdir);
 			if ((fd = mkstemp(tempname)) == -1 ||
 			    (fout = Fdopen(fd, "a")) == NULL) {
 				warn("%s", tempname);
@@ -264,29 +262,29 @@ outof(names, fo, hp)
 				goto cant;
 			}
 			image = open(tempname, O_RDWR);
-			(void) rm(tempname);
+			(void)rm(tempname);
 			if (image < 0) {
 				warn("%s", tempname);
 				senderr++;
-				(void) Fclose(fout);
+				(void)Fclose(fout);
 				goto cant;
 			}
-			(void) fcntl(image, F_SETFD, 1);
+			(void)fcntl(image, F_SETFD, 1);
 			fprintf(fout, "From %s %s", myname, date);
 			puthead(hp, fout,
-				GTO|GSUBJECT|GCC|GREPLYTO|GINREPLYTO|GNL);
+			    GTO|GSUBJECT|GCC|GREPLYTO|GINREPLYTO|GNL);
 			while ((c = getc(fo)) != EOF)
-				(void) putc(c, fout);
+				(void)putc(c, fout);
 			rewind(fo);
-			(void) putc('\n', fout);
-			(void) fflush(fout);
+			fprintf(fout, "\n");
+			(void)fflush(fout);
 			if (ferror(fout)) {
 				warn("%s", tempname);
 				senderr++;
-				Fclose(fout);
+				(void)Fclose(fout);
 				goto cant;
 			}
-			(void) Fclose(fout);
+			(void)Fclose(fout);
 		}
 
 		/*
@@ -297,7 +295,7 @@ outof(names, fo, hp)
 
 		if (ispipe) {
 			int pid;
-			char *shell;
+			char *sh;
 
 			/*
 			 * XXX
@@ -306,11 +304,11 @@ outof(names, fo, hp)
 			 * share the same lseek location and trample
 			 * on one another.
 			 */
-			if ((shell = value("SHELL")) == NOSTR)
-				shell = _PATH_CSHELL;
-			pid = start_command(shell, sigmask(SIGHUP)|
-					sigmask(SIGINT)|sigmask(SIGQUIT),
-				image, -1, "-c", fname, NOSTR);
+			if ((sh = value("SHELL")) == NULL)
+				sh = _PATH_CSHELL;
+			pid = start_command(sh,
+			    sigmask(SIGHUP)|sigmask(SIGINT)|sigmask(SIGQUIT),
+			    image, -1, "-c", fname, NULL);
 			if (pid < 0) {
 				senderr++;
 				goto cant;
@@ -330,22 +328,22 @@ outof(names, fo, hp)
 				fin = Fdopen(f, "r");
 			if (fin == NULL) {
 				fprintf(stderr, "Can't reopen image\n");
-				(void) Fclose(fout);
+				(void)Fclose(fout);
 				senderr++;
 				goto cant;
 			}
 			rewind(fin);
 			while ((c = getc(fin)) != EOF)
-				(void) putc(c, fout);
+				(void)putc(c, fout);
 			if (ferror(fout)) {
 				warnx("%s", fname);
 				senderr++;
-				Fclose(fout);
-				Fclose(fin);
+				(void)Fclose(fout);
+				(void)Fclose(fin);
 				goto cant;
 			}
-			(void) Fclose(fout);
-			(void) Fclose(fin);
+			(void)Fclose(fout);
+			(void)Fclose(fin);
 		}
 cant:
 		/*
@@ -357,10 +355,10 @@ cant:
 		np = np->n_flink;
 	}
 	if (image >= 0) {
-		(void) close(image);
+		(void)close(image);
 		image = -1;
 	}
-	return(top);
+	return (top);
 }
 
 /*
@@ -372,17 +370,17 @@ int
 isfileaddr(name)
 	char *name;
 {
-	register char *cp;
+	char *cp;
 
 	if (*name == '+')
-		return 1;
-	for (cp = name; *cp; cp++) {
+		return (1);
+	for (cp = name; *cp != '\0'; cp++) {
 		if (*cp == '!' || *cp == '%' || *cp == '@')
-			return 0;
+			return (0);
 		if (*cp == '/')
-			return 1;
+			return (1);
 	}
-	return 0;
+	return (0);
 }
 
 /*
@@ -396,14 +394,14 @@ struct name *
 usermap(names)
 	struct name *names;
 {
-	register struct name *new, *np, *cp;
+	struct name *new, *np, *cp;
 	struct grouphead *gh;
-	register int metoo;
+	int metoo;
 
-	new = NIL;
+	new = NULL;
 	np = names;
-	metoo = (value("metoo") != NOSTR);
-	while (np != NIL) {
+	metoo = (value("metoo") != NULL);
+	while (np != NULL) {
 		if (np->n_name[0] == '\\') {
 			cp = np->n_flink;
 			new = put(new, np);
@@ -412,13 +410,13 @@ usermap(names)
 		}
 		gh = findgroup(np->n_name);
 		cp = np->n_flink;
-		if (gh != NOGRP)
+		if (gh != NULL)
 			new = gexpand(new, gh, metoo, np->n_type);
 		else
 			new = put(new, np);
 		np = cp;
 	}
-	return(new);
+	return (new);
 }
 
 /*
@@ -441,16 +439,16 @@ gexpand(nlist, gh, metoo, ntype)
 
 	if (depth > MAXEXP) {
 		printf("Expanding alias to depth larger than %d\n", MAXEXP);
-		return(nlist);
+		return (nlist);
 	}
 	depth++;
-	for (gp = gh->g_list; gp != NOGE; gp = gp->ge_link) {
+	for (gp = gh->g_list; gp != NULL; gp = gp->ge_link) {
 		cp = gp->ge_name;
 		if (*cp == '\\')
 			goto quote;
 		if (strcmp(cp, gh->g_name) == 0)
 			goto quote;
-		if ((ngh = findgroup(cp)) != NOGRP) {
+		if ((ngh = findgroup(cp)) != NULL) {
 			nlist = gexpand(nlist, ngh, metoo, ntype);
 			continue;
 		}
@@ -460,7 +458,7 @@ quote:
 		 * At this point should allow to expand
 		 * to self if only person in group
 		 */
-		if (gp == gh->g_list && gp->ge_link == NOGE)
+		if (gp == gh->g_list && gp->ge_link == NULL)
 			goto skip;
 		if (!metoo && strcmp(cp, myname) == 0)
 			np->n_type |= GDEL;
@@ -468,7 +466,7 @@ skip:
 		nlist = put(nlist, np);
 	}
 	depth--;
-	return(nlist);
+	return (nlist);
 }
 
 /*
@@ -478,16 +476,16 @@ struct name *
 cat(n1, n2)
 	struct name *n1, *n2;
 {
-	register struct name *tail;
+	struct name *tail;
 
-	if (n1 == NIL)
-		return(n2);
-	if (n2 == NIL)
-		return(n1);
+	if (n1 == NULL)
+		return (n2);
+	if (n2 == NULL)
+		return (n1);
 	tail = tailof(n1);
 	tail->n_flink = n2;
 	n2->n_blink = tail;
-	return(n1);
+	return (n1);
 }
 
 /*
@@ -498,8 +496,8 @@ char **
 unpack(np)
 	struct name *np;
 {
-	register char **ap, **top;
-	register struct name *n;
+	char **ap, **top;
+	struct name *n;
 	int t, extra, metoo, verbose;
 
 	n = np;
@@ -513,13 +511,13 @@ unpack(np)
 	 */
 	extra = 2;
 	extra++;
-	metoo = value("metoo") != NOSTR;
+	metoo = value("metoo") != NULL;
 	if (metoo)
 		extra++;
-	verbose = value("verbose") != NOSTR;
+	verbose = value("verbose") != NULL;
 	if (verbose)
 		extra++;
-	top = (char **) salloc((t + extra) * sizeof *top);
+	top = (char **)salloc((t + extra) * sizeof(*top));
 	ap = top;
 	*ap++ = "send-mail";
 	*ap++ = "-i";
@@ -527,11 +525,11 @@ unpack(np)
 		*ap++ = "-m";
 	if (verbose)
 		*ap++ = "-v";
-	for (; n != NIL; n = n->n_flink)
+	for (; n != NULL; n = n->n_flink)
 		if ((n->n_type & GDEL) == 0)
 			*ap++ = n->n_name;
-	*ap = NOSTR;
-	return(top);
+	*ap = NULL;
+	return (top);
 }
 
 /*
@@ -543,21 +541,21 @@ struct name *
 elide(names)
 	struct name *names;
 {
-	register struct name *np, *t, *new;
+	struct name *np, *t, *new;
 	struct name *x;
 
-	if (names == NIL)
-		return(NIL);
+	if (names == NULL)
+		return (NULL);
 	new = names;
 	np = names;
 	np = np->n_flink;
-	if (np != NIL)
-		np->n_blink = NIL;
-	new->n_flink = NIL;
-	while (np != NIL) {
+	if (np != NULL)
+		np->n_blink = NULL;
+	new->n_flink = NULL;
+	while (np != NULL) {
 		t = new;
 		while (strcasecmp(t->n_name, np->n_name) < 0) {
-			if (t->n_flink == NIL)
+			if (t->n_flink == NULL)
 				break;
 			t = t->n_flink;
 		}
@@ -572,7 +570,7 @@ elide(names)
 			np->n_blink = t;
 			t = np;
 			np = np->n_flink;
-			t->n_flink = NIL;
+			t->n_flink = NULL;
 			continue;
 		}
 
@@ -587,7 +585,7 @@ elide(names)
 			np = np->n_flink;
 			t->n_flink = new;
 			new->n_blink = t;
-			t->n_blink = NIL;
+			t->n_blink = NULL;
 			new = t;
 			continue;
 		}
@@ -611,12 +609,12 @@ elide(names)
 	 */
 
 	np = new;
-	while (np != NIL) {
+	while (np != NULL) {
 		t = np;
-		while (t->n_flink != NIL &&
-		       strcasecmp(np->n_name, t->n_flink->n_name) == 0)
+		while (t->n_flink != NULL &&
+		    strcasecmp(np->n_name, t->n_flink->n_name) == 0)
 			t = t->n_flink;
-		if (t == np || t == NIL) {
+		if (t == np || t == NULL) {
 			np = np->n_flink;
 			continue;
 		}
@@ -627,11 +625,11 @@ elide(names)
 		 */
 
 		np->n_flink = t->n_flink;
-		if (t->n_flink != NIL)
+		if (t->n_flink != NULL)
 			t->n_flink->n_blink = np;
 		np = np->n_flink;
 	}
-	return(new);
+	return (new);
 }
 
 /*
@@ -643,10 +641,10 @@ put(list, node)
 	struct name *list, *node;
 {
 	node->n_flink = list;
-	node->n_blink = NIL;
-	if (list != NIL)
+	node->n_blink = NULL;
+	if (list != NULL)
 		list->n_blink = node;
-	return(node);
+	return (node);
 }
 
 /*
@@ -655,14 +653,14 @@ put(list, node)
  */
 int
 count(np)
-	register struct name *np;
+	struct name *np;
 {
-	register int c;
+	int c;
 
-	for (c = 0; np != NIL; np = np->n_flink)
+	for (c = 0; np != NULL; np = np->n_flink)
 		if ((np->n_type & GDEL) == 0)
 			c++;
-	return c;
+	return (c);
 }
 
 /*
@@ -670,28 +668,28 @@ count(np)
  */
 struct name *
 delname(np, name)
-	register struct name *np;
+	struct name *np;
 	char name[];
 {
-	register struct name *p;
+	struct name *p;
 
-	for (p = np; p != NIL; p = p->n_flink)
+	for (p = np; p != NULL; p = p->n_flink)
 		if (strcasecmp(p->n_name, name) == 0) {
-			if (p->n_blink == NIL) {
-				if (p->n_flink != NIL)
-					p->n_flink->n_blink = NIL;
+			if (p->n_blink == NULL) {
+				if (p->n_flink != NULL)
+					p->n_flink->n_blink = NULL;
 				np = p->n_flink;
 				continue;
 			}
-			if (p->n_flink == NIL) {
-				if (p->n_blink != NIL)
-					p->n_blink->n_flink = NIL;
+			if (p->n_flink == NULL) {
+				if (p->n_blink != NULL)
+					p->n_blink->n_flink = NULL;
 				continue;
 			}
 			p->n_blink->n_flink = p->n_flink;
 			p->n_flink->n_blink = p->n_blink;
 		}
-	return np;
+	return (np);
 }
 
 /*
@@ -704,10 +702,10 @@ void
 prettyprint(name)
 	struct name *name;
 {
-	register struct name *np;
+	struct name *np;
 
 	np = name;
-	while (np != NIL) {
+	while (np != NULL) {
 		fprintf(stderr, "%s(%d) ", np->n_name, np->n_type);
 		np = np->n_flink;
 	}
diff --git a/usr.bin/mail/pathnames.h b/usr.bin/mail/pathnames.h
index 40f02fb..57a2a0c 100644
--- a/usr.bin/mail/pathnames.h
+++ b/usr.bin/mail/pathnames.h
@@ -35,8 +35,6 @@
  * $FreeBSD$
  */
 
-#include <paths.h>
-
 #define	_PATH_EX	"/usr/bin/ex"
 #define	_PATH_HELP	"/usr/share/misc/mail.help"
 #define	_PATH_TILDE	"/usr/share/misc/mail.tildehelp"
diff --git a/usr.bin/mail/popen.c b/usr.bin/mail/popen.c
index 8ba870b..e8ee364 100644
--- a/usr.bin/mail/popen.c
+++ b/usr.bin/mail/popen.c
@@ -48,19 +48,19 @@ static const char rcsid[] =
 #define WRITE 1
 
 struct fp {
-	FILE *fp;
-	int pipe;
-	int pid;
-	struct fp *link;
+	FILE	*fp;
+	int	pipe;
+	int	pid;
+	struct	fp *link;
 };
 static struct fp *fp_head;
 
 struct child {
-	int pid;
-	char done;
-	char free;
-	int status;
-	struct child *link;
+	int	pid;
+	char	done;
+	char	free;
+	int	status;
+	struct	child *link;
 };
 static struct child *child;
 static struct child *findchild __P((int));
@@ -68,30 +68,30 @@ static void delchild __P((struct child *));
 static int file_pid __P((FILE *));
 
 FILE *
-Fopen(file, mode)
-	char *file, *mode;
+Fopen(path, mode)
+	const char *path, *mode;
 {
 	FILE *fp;
 
-	if ((fp = fopen(file, mode)) != NULL) {
+	if ((fp = fopen(path, mode)) != NULL) {
 		register_file(fp, 0, 0);
-		(void) fcntl(fileno(fp), F_SETFD, 1);
+		(void)fcntl(fileno(fp), F_SETFD, 1);
 	}
-	return fp;
+	return (fp);
 }
 
 FILE *
 Fdopen(fd, mode)
 	int fd;
-	char *mode;
+	const char *mode;
 {
 	FILE *fp;
 
 	if ((fp = fdopen(fd, mode)) != NULL) {
 		register_file(fp, 0, 0);
-		(void) fcntl(fileno(fp), F_SETFD, 1);
+		(void)fcntl(fileno(fp), F_SETFD, 1);
 	}
-	return fp;
+	return (fp);
 }
 
 int
@@ -99,13 +99,13 @@ Fclose(fp)
 	FILE *fp;
 {
 	unregister_file(fp);
-	return fclose(fp);
+	return (fclose(fp));
 }
 
 FILE *
 Popen(cmd, mode)
 	char *cmd;
-	char *mode;
+	const char *mode;
 {
 	int p[2];
 	int myside, hisside, fd0, fd1;
@@ -113,9 +113,9 @@ Popen(cmd, mode)
 	FILE *fp;
 
 	if (pipe(p) < 0)
-		return NULL;
-	(void) fcntl(p[READ], F_SETFD, 1);
-	(void) fcntl(p[WRITE], F_SETFD, 1);
+		return (NULL);
+	(void)fcntl(p[READ], F_SETFD, 1);
+	(void)fcntl(p[WRITE], F_SETFD, 1);
 	if (*mode == 'r') {
 		myside = p[READ];
 		fd0 = -1;
@@ -125,15 +125,15 @@ Popen(cmd, mode)
 		hisside = fd0 = p[READ];
 		fd1 = -1;
 	}
-	if ((pid = start_command(cmd, 0, fd0, fd1, NOSTR, NOSTR, NOSTR)) < 0) {
-		close(p[READ]);
-		close(p[WRITE]);
-		return NULL;
+	if ((pid = start_command(cmd, 0, fd0, fd1, NULL, NULL, NULL)) < 0) {
+		(void)close(p[READ]);
+		(void)close(p[WRITE]);
+		return (NULL);
 	}
-	(void) close(hisside);
+	(void)close(hisside);
 	if ((fp = fdopen(myside, mode)) != NULL)
 		register_file(fp, 1, pid);
-	return fp;
+	return (fp);
 }
 
 int
@@ -145,22 +145,22 @@ Pclose(ptr)
 
 	i = file_pid(ptr);
 	unregister_file(ptr);
-	(void) fclose(ptr);
+	(void)fclose(ptr);
 	omask = sigblock(sigmask(SIGINT)|sigmask(SIGHUP));
 	i = wait_child(i);
-	sigsetmask(omask);
-	return i;
+	(void)sigsetmask(omask);
+	return (i);
 }
 
 void
 close_all_files()
 {
 
-	while (fp_head)
+	while (fp_head != NULL)
 		if (fp_head->pipe)
-			(void) Pclose(fp_head->fp);
+			(void)Pclose(fp_head->fp);
 		else
-			(void) Fclose(fp_head->fp);
+			(void)Fclose(fp_head->fp);
 }
 
 void
@@ -170,7 +170,7 @@ register_file(fp, pipe, pid)
 {
 	struct fp *fpp;
 
-	if ((fpp = (struct fp *) malloc(sizeof *fpp)) == NULL)
+	if ((fpp = malloc(sizeof(*fpp))) == NULL)
 		err(1, "Out of memory");
 	fpp->fp = fp;
 	fpp->pipe = pipe;
@@ -185,10 +185,10 @@ unregister_file(fp)
 {
 	struct fp **pp, *p;
 
-	for (pp = &fp_head; p = *pp; pp = &p->link)
+	for (pp = &fp_head; (p = *pp) != NULL; pp = &p->link)
 		if (p->fp == fp) {
 			*pp = p->link;
-			free((char *) p);
+			(void)free(p);
 			return;
 		}
 	errx(1, "Invalid file pointer");
@@ -201,7 +201,7 @@ file_pid(fp)
 {
 	struct fp *p;
 
-	for (p = fp_head; p; p = p->link)
+	for (p = fp_head; p != NULL; p = p->link)
 		if (p->fp == fp)
 			return (p->pid);
 	errx(1, "Invalid file pointer");
@@ -225,8 +225,8 @@ run_command(cmd, mask, infd, outfd, a0, a1, a2)
 	int pid;
 
 	if ((pid = start_command(cmd, mask, infd, outfd, a0, a1, a2)) < 0)
-		return -1;
-	return wait_command(pid);
+		return (-1);
+	return (wait_command(pid));
 }
 
 /*VARARGS4*/
@@ -240,22 +240,22 @@ start_command(cmd, mask, infd, outfd, a0, a1, a2)
 
 	if ((pid = fork()) < 0) {
 		warn("fork");
-		return -1;
+		return (-1);
 	}
 	if (pid == 0) {
 		char *argv[100];
-		int i = getrawlist(cmd, argv, sizeof argv / sizeof *argv);
+		int i = getrawlist(cmd, argv, sizeof(argv) / sizeof(*argv));
 
-		if ((argv[i++] = a0) != NOSTR &&
-		    (argv[i++] = a1) != NOSTR &&
-		    (argv[i++] = a2) != NOSTR)
-			argv[i] = NOSTR;
+		if ((argv[i++] = a0) != NULL &&
+		    (argv[i++] = a1) != NULL &&
+		    (argv[i++] = a2) != NULL)
+			argv[i] = NULL;
 		prepare_child(mask, infd, outfd);
 		execvp(argv[0], argv);
 		warn("%s", argv[0]);
 		_exit(1);
 	}
-	return pid;
+	return (pid);
 }
 
 void
@@ -274,10 +274,10 @@ prepare_child(mask, infd, outfd)
 		dup2(outfd, 1);
 	for (i = 1; i <= NSIG; i++)
 		if (mask & sigmask(i))
-			(void) signal(i, SIG_IGN);
+			(void)signal(i, SIG_IGN);
 	if ((mask & sigmask(SIGINT)) == 0)
-		(void) signal(SIGINT, SIG_DFL);
-	(void) sigsetmask(0);
+		(void)signal(SIGINT, SIG_DFL);
+	(void)sigsetmask(0);
 }
 
 int
@@ -287,50 +287,51 @@ wait_command(pid)
 
 	if (wait_child(pid) < 0) {
 		printf("Fatal error in process.\n");
-		return -1;
+		return (-1);
 	}
-	return 0;
+	return (0);
 }
 
 static struct child *
 findchild(pid)
 	int pid;
 {
-	register struct child **cpp;
+	struct child **cpp;
 
 	for (cpp = &child; *cpp != NULL && (*cpp)->pid != pid;
-	     cpp = &(*cpp)->link)
+	    cpp = &(*cpp)->link)
 			;
 	if (*cpp == NULL) {
-		*cpp = (struct child *) malloc(sizeof (struct child));
+		*cpp = malloc(sizeof(struct child));
 		if (*cpp == NULL)
 			err(1, "Out of memory");
 		(*cpp)->pid = pid;
 		(*cpp)->done = (*cpp)->free = 0;
 		(*cpp)->link = NULL;
 	}
-	return *cpp;
+	return (*cpp);
 }
 
 static void
 delchild(cp)
-	register struct child *cp;
+	struct child *cp;
 {
-	register struct child **cpp;
+	struct child **cpp;
 
 	for (cpp = &child; *cpp != cp; cpp = &(*cpp)->link)
 		;
 	*cpp = cp->link;
-	free((char *) cp);
+	(void)free(cp);
 }
 
+/*ARGSUSED*/
 void
 sigchild(signo)
 	int signo;
 {
 	int pid;
 	int status;
-	register struct child *cp;
+	struct child *cp;
 
 	while ((pid = waitpid((pid_t)-1, &status, WNOHANG)) > 0) {
 		cp = findchild(pid);
@@ -353,14 +354,14 @@ wait_child(pid)
 	int pid;
 {
 	int mask = sigblock(sigmask(SIGCHLD));
-	register struct child *cp = findchild(pid);
+	struct child *cp = findchild(pid);
 
 	while (!cp->done)
 		sigpause(mask);
 	wait_status = cp->status;
 	delchild(cp);
-	sigsetmask(mask);
-	return((WIFEXITED(wait_status) && WEXITSTATUS(wait_status)) ? -1 : 0);
+	(void)sigsetmask(mask);
+	return ((WIFEXITED(wait_status) && WEXITSTATUS(wait_status)) ? -1 : 0);
 }
 
 /*
@@ -371,11 +372,11 @@ free_child(pid)
 	int pid;
 {
 	int mask = sigblock(sigmask(SIGCHLD));
-	register struct child *cp = findchild(pid);
+	struct child *cp = findchild(pid);
 
 	if (cp->done)
 		delchild(cp);
 	else
 		cp->free = 1;
-	sigsetmask(mask);
+	(void)sigsetmask(mask);
 }
diff --git a/usr.bin/mail/quit.c b/usr.bin/mail/quit.c
index 66331fc..f2ba618 100644
--- a/usr.bin/mail/quit.c
+++ b/usr.bin/mail/quit.c
@@ -60,8 +60,8 @@ quitcmd()
 	 * Otherwise, return -1 to abort command loop.
 	 */
 	if (sourcing)
-		return 1;
-	return -1;
+		return (1);
+	return (-1);
 }
 
 /*
@@ -74,9 +74,8 @@ quit()
 {
 	int mcount, p, modify, autohold, anystat, holdbit, nohold;
 	FILE *ibuf, *obuf, *fbuf, *rbuf, *readstat, *abuf;
-	register struct message *mp;
-	register int c;
-	int fd;
+	struct message *mp;
+	int c, fd;
 	struct stat minfo;
 	char *mbox, tempname[PATHSIZE];
 
@@ -108,31 +107,32 @@ quit()
 	fbuf = Fopen(mailname, "r");
 	if (fbuf == NULL)
 		goto newmail;
-	flock(fileno(fbuf), LOCK_EX);
+	(void)flock(fileno(fbuf), LOCK_EX);
 	rbuf = NULL;
 	if (fstat(fileno(fbuf), &minfo) >= 0 && minfo.st_size > mailsize) {
 		printf("New mail has arrived.\n");
-		snprintf(tempname, sizeof(tempname), "%s/mail.RqXXXXXXXXXX", tmpdir);
+		(void)snprintf(tempname, sizeof(tempname),
+		    "%s/mail.RqXXXXXXXXXX", tmpdir);
 		if ((fd = mkstemp(tempname)) == -1 ||
 		    (rbuf = Fdopen(fd, "w")) == NULL)
 			goto newmail;
 #ifdef APPEND
-		fseek(fbuf, (long)mailsize, 0);
+		(void)fseek(fbuf, (long)mailsize, 0);
 		while ((c = getc(fbuf)) != EOF)
-			(void) putc(c, rbuf);
+			(void)putc(c, rbuf);
 #else
 		p = minfo.st_size - mailsize;
 		while (p-- > 0) {
 			c = getc(fbuf);
 			if (c == EOF)
 				goto newmail;
-			(void) putc(c, rbuf);
+			(void)putc(c, rbuf);
 		}
 #endif
-		Fclose(rbuf);
+		(void)Fclose(rbuf);
 		if ((rbuf = Fopen(tempname, "r")) == NULL)
 			goto newmail;
-		rm(tempname);
+		(void)rm(tempname);
 	}
 
 	/*
@@ -140,10 +140,10 @@ quit()
 	 */
 
 	anystat = 0;
-	autohold = value("hold") != NOSTR;
+	autohold = value("hold") != NULL;
 	holdbit = autohold ? MPRESERVE : MBOX;
 	nohold = MBOX|MSAVED|MDELETED|MPRESERVE;
-	if (value("keepsave") != NOSTR)
+	if (value("keepsave") != NULL)
 		nohold &= ~MSAVED;
 	for (mp = &message[0]; mp < &message[msgCount]; mp++) {
 		if (mp->m_flag & MNEW) {
@@ -158,9 +158,9 @@ quit()
 			mp->m_flag |= holdbit;
 	}
 	modify = 0;
-	if (Tflag != NOSTR) {
+	if (Tflag != NULL) {
 		if ((readstat = Fopen(Tflag, "w")) == NULL)
-			Tflag = NOSTR;
+			Tflag = NULL;
 	}
 	for (c = 0, p = 0, mp = &message[0]; mp < &message[msgCount]; mp++) {
 		if (mp->m_flag & MBOX)
@@ -169,25 +169,25 @@ quit()
 			p++;
 		if (mp->m_flag & MODIFY)
 			modify++;
-		if (Tflag != NOSTR && (mp->m_flag & (MREAD|MDELETED)) != 0) {
+		if (Tflag != NULL && (mp->m_flag & (MREAD|MDELETED)) != 0) {
 			char *id;
 
-			if ((id = hfield("article-id", mp)) != NOSTR)
+			if ((id = hfield("article-id", mp)) != NULL)
 				fprintf(readstat, "%s\n", id);
 		}
 	}
-	if (Tflag != NOSTR)
-		Fclose(readstat);
+	if (Tflag != NULL)
+		(void)Fclose(readstat);
 	if (p == msgCount && !modify && !anystat) {
 		printf("Held %d message%s in %s\n",
 			p, p == 1 ? "" : "s", mailname);
-		Fclose(fbuf);
+		(void)Fclose(fbuf);
 		return;
 	}
 	if (c == 0) {
 		if (p != 0) {
 			writeback(rbuf);
-			Fclose(fbuf);
+			(void)Fclose(fbuf);
 			return;
 		}
 		goto cream;
@@ -202,58 +202,59 @@ quit()
 
 	mbox = expand("&");
 	mcount = c;
-	if (value("append") == NOSTR) {
-		snprintf(tempname, sizeof(tempname), "%s/mail.RmXXXXXXXXXX", tmpdir);
+	if (value("append") == NULL) {
+		(void)snprintf(tempname, sizeof(tempname),
+		    "%s/mail.RmXXXXXXXXXX", tmpdir);
 		if ((fd = mkstemp(tempname)) == -1 ||
 		    (obuf = Fdopen(fd, "w")) == NULL) {
 			warn("%s", tempname);
-			Fclose(fbuf);
+			(void)Fclose(fbuf);
 			return;
 		}
 		if ((ibuf = Fopen(tempname, "r")) == NULL) {
 			warn("%s", tempname);
-			rm(tempname);
-			Fclose(obuf);
-			Fclose(fbuf);
+			(void)rm(tempname);
+			(void)Fclose(obuf);
+			(void)Fclose(fbuf);
 			return;
 		}
-		rm(tempname);
+		(void)rm(tempname);
 		if ((abuf = Fopen(mbox, "r")) != NULL) {
 			while ((c = getc(abuf)) != EOF)
-				(void) putc(c, obuf);
-			Fclose(abuf);
+				(void)putc(c, obuf);
+			(void)Fclose(abuf);
 		}
 		if (ferror(obuf)) {
 			warnx("%s", tempname);
-			Fclose(ibuf);
-			Fclose(obuf);
-			Fclose(fbuf);
+			(void)Fclose(ibuf);
+			(void)Fclose(obuf);
+			(void)Fclose(fbuf);
 			return;
 		}
-		Fclose(obuf);
-		close(open(mbox, O_CREAT | O_TRUNC | O_WRONLY, 0600));
+		(void)Fclose(obuf);
+		(void)close(open(mbox, O_CREAT | O_TRUNC | O_WRONLY, 0600));
 		if ((obuf = Fopen(mbox, "r+")) == NULL) {
 			warn("%s", mbox);
-			Fclose(ibuf);
-			Fclose(fbuf);
+			(void)Fclose(ibuf);
+			(void)Fclose(fbuf);
 			return;
 		}
 	}
-	if (value("append") != NOSTR) {
+	if (value("append") != NULL) {
 		if ((obuf = Fopen(mbox, "a")) == NULL) {
 			warn("%s", mbox);
-			Fclose(fbuf);
+			(void)Fclose(fbuf);
 			return;
 		}
-		fchmod(fileno(obuf), 0600);
+		(void)fchmod(fileno(obuf), 0600);
 	}
 	for (mp = &message[0]; mp < &message[msgCount]; mp++)
 		if (mp->m_flag & MBOX)
-			if (sendmessage(mp, obuf, saveignore, NOSTR) < 0) {
+			if (sendmessage(mp, obuf, saveignore, NULL) < 0) {
 				warnx("%s", mbox);
-				Fclose(ibuf);
-				Fclose(obuf);
-				Fclose(fbuf);
+				(void)Fclose(ibuf);
+				(void)Fclose(obuf);
+				(void)Fclose(fbuf);
 				return;
 			}
 
@@ -263,26 +264,26 @@ quit()
 	 * If we are appending, this is unnecessary.
 	 */
 
-	if (value("append") == NOSTR) {
+	if (value("append") == NULL) {
 		rewind(ibuf);
 		c = getc(ibuf);
 		while (c != EOF) {
-			(void) putc(c, obuf);
+			(void)putc(c, obuf);
 			if (ferror(obuf))
 				break;
 			c = getc(ibuf);
 		}
-		Fclose(ibuf);
-		fflush(obuf);
+		(void)Fclose(ibuf);
+		(void)fflush(obuf);
 	}
 	trunc(obuf);
 	if (ferror(obuf)) {
 		warn("%s", mbox);
-		Fclose(obuf);
-		Fclose(fbuf);
+		(void)Fclose(obuf);
+		(void)Fclose(fbuf);
 		return;
 	}
-	Fclose(obuf);
+	(void)Fclose(obuf);
 	if (mcount == 1)
 		printf("Saved 1 message in mbox\n");
 	else
@@ -295,12 +296,12 @@ quit()
 
 	if (p != 0) {
 		writeback(rbuf);
-		Fclose(fbuf);
+		(void)Fclose(fbuf);
 		return;
 	}
 
 	/*
-	 * Finally, remove his /usr/mail file.
+	 * Finally, remove his /var/mail file.
 	 * If new mail has arrived, copy it back.
 	 */
 
@@ -310,22 +311,22 @@ cream:
 		if (abuf == NULL)
 			goto newmail;
 		while ((c = getc(rbuf)) != EOF)
-			(void) putc(c, abuf);
-		Fclose(rbuf);
+			(void)putc(c, abuf);
+		(void)Fclose(rbuf);
 		trunc(abuf);
-		Fclose(abuf);
+		(void)Fclose(abuf);
 		alter(mailname);
-		Fclose(fbuf);
+		(void)Fclose(fbuf);
 		return;
 	}
 	demail();
-	Fclose(fbuf);
+	(void)Fclose(fbuf);
 	return;
 
 newmail:
 	printf("Thou hast new mail.\n");
 	if (fbuf != NULL)
-		Fclose(fbuf);
+		(void)Fclose(fbuf);
 }
 
 /*
@@ -336,52 +337,52 @@ newmail:
  */
 int
 writeback(res)
-	register FILE *res;
+	FILE *res;
 {
-	register struct message *mp;
-	register int p, c;
+	struct message *mp;
+	int p, c;
 	FILE *obuf;
 
 	p = 0;
 	if ((obuf = Fopen(mailname, "r+")) == NULL) {
 		warn("%s", mailname);
-		return(-1);
+		return (-1);
 	}
 #ifndef APPEND
 	if (res != NULL)
 		while ((c = getc(res)) != EOF)
-			(void) putc(c, obuf);
+			(void)putc(c, obuf);
 #endif
 	for (mp = &message[0]; mp < &message[msgCount]; mp++)
 		if ((mp->m_flag&MPRESERVE)||(mp->m_flag&MTOUCH)==0) {
 			p++;
-			if (sendmessage(mp, obuf, (struct ignoretab *)0, NOSTR) < 0) {
+			if (sendmessage(mp, obuf, NULL, NULL) < 0) {
 				warnx("%s", mailname);
-				Fclose(obuf);
-				return(-1);
+				(void)Fclose(obuf);
+				return (-1);
 			}
 		}
 #ifdef APPEND
 	if (res != NULL)
 		while ((c = getc(res)) != EOF)
-			(void) putc(c, obuf);
+			(void)putc(c, obuf);
 #endif
-	fflush(obuf);
+	(void)fflush(obuf);
 	trunc(obuf);
 	if (ferror(obuf)) {
 		warn("%s", mailname);
-		Fclose(obuf);
-		return(-1);
+		(void)Fclose(obuf);
+		return (-1);
 	}
 	if (res != NULL)
-		Fclose(res);
-	Fclose(obuf);
+		(void)Fclose(res);
+	(void)Fclose(obuf);
 	alter(mailname);
 	if (p == 1)
 		printf("Held 1 message in %s\n", mailname);
 	else
 		printf("Held %d messages in %s\n", p, mailname);
-	return(0);
+	return (0);
 }
 
 /*
@@ -391,8 +392,8 @@ writeback(res)
 void
 edstop()
 {
-	register int gotcha, c;
-	register struct message *mp;
+	int gotcha, c;
+	struct message *mp;
 	FILE *obuf, *ibuf, *readstat;
 	struct stat statb;
 	char tempname[PATHSIZE];
@@ -400,9 +401,9 @@ edstop()
 	if (readonly)
 		return;
 	holdsigs();
-	if (Tflag != NOSTR) {
+	if (Tflag != NULL) {
 		if ((readstat = Fopen(Tflag, "w")) == NULL)
-			Tflag = NOSTR;
+			Tflag = NULL;
 	}
 	for (mp = &message[0], gotcha = 0; mp < &message[msgCount]; mp++) {
 		if (mp->m_flag & MNEW) {
@@ -411,49 +412,51 @@ edstop()
 		}
 		if (mp->m_flag & (MODIFY|MDELETED|MSTATUS))
 			gotcha++;
-		if (Tflag != NOSTR && (mp->m_flag & (MREAD|MDELETED)) != 0) {
+		if (Tflag != NULL && (mp->m_flag & (MREAD|MDELETED)) != 0) {
 			char *id;
 
-			if ((id = hfield("article-id", mp)) != NOSTR)
+			if ((id = hfield("article-id", mp)) != NULL)
 				fprintf(readstat, "%s\n", id);
 		}
 	}
-	if (Tflag != NOSTR)
-		Fclose(readstat);
-	if (!gotcha || Tflag != NOSTR)
+	if (Tflag != NULL)
+		(void)Fclose(readstat);
+	if (!gotcha || Tflag != NULL)
 		goto done;
 	ibuf = NULL;
 	if (stat(mailname, &statb) >= 0 && statb.st_size > mailsize) {
 		int fd;
 
-		snprintf(tempname, sizeof(tempname), "%s/mbox.XXXXXXXXXX", tmpdir);
-		if ((fd = mkstemp(tempname)) == -1 || (obuf = Fdopen(fd, "w")) == NULL) {
+		(void)snprintf(tempname, sizeof(tempname),
+		    "%s/mbox.XXXXXXXXXX", tmpdir);
+		if ((fd = mkstemp(tempname)) == -1 ||
+		    (obuf = Fdopen(fd, "w")) == NULL) {
 			warn("%s", tempname);
 			relsesigs();
 			reset(0);
 		}
 		if ((ibuf = Fopen(mailname, "r")) == NULL) {
 			warn("%s", mailname);
-			Fclose(obuf);
-			rm(tempname);
+			(void)Fclose(obuf);
+			(void)rm(tempname);
 			relsesigs();
 			reset(0);
 		}
-		fseek(ibuf, (long)mailsize, 0);
+		(void)fseek(ibuf, (long)mailsize, 0);
 		while ((c = getc(ibuf)) != EOF)
-			(void) putc(c, obuf);
-		Fclose(ibuf);
-		Fclose(obuf);
+			(void)putc(c, obuf);
+		(void)Fclose(ibuf);
+		(void)Fclose(obuf);
 		if ((ibuf = Fopen(tempname, "r")) == NULL) {
 			warn("%s", tempname);
-			rm(tempname);
+			(void)rm(tempname);
 			relsesigs();
 			reset(0);
 		}
-		rm(tempname);
+		(void)rm(tempname);
 	}
 	printf("\"%s\" ", mailname);
-	fflush(stdout);
+	(void)fflush(stdout);
 	if ((obuf = Fopen(mailname, "r+")) == NULL) {
 		warn("%s", mailname);
 		relsesigs();
@@ -465,7 +468,7 @@ edstop()
 		if ((mp->m_flag & MDELETED) != 0)
 			continue;
 		c++;
-		if (sendmessage(mp, obuf, (struct ignoretab *) NULL, NOSTR) < 0) {
+		if (sendmessage(mp, obuf, NULL, NULL) < 0) {
 			warnx("%s", mailname);
 			relsesigs();
 			reset(0);
@@ -474,22 +477,22 @@ edstop()
 	gotcha = (c == 0 && ibuf == NULL);
 	if (ibuf != NULL) {
 		while ((c = getc(ibuf)) != EOF)
-			(void) putc(c, obuf);
-		Fclose(ibuf);
+			(void)putc(c, obuf);
+		(void)Fclose(ibuf);
 	}
-	fflush(obuf);
+	(void)fflush(obuf);
 	if (ferror(obuf)) {
 		warn("%s", mailname);
 		relsesigs();
 		reset(0);
 	}
-	Fclose(obuf);
+	(void)Fclose(obuf);
 	if (gotcha) {
-		rm(mailname);
+		(void)rm(mailname);
 		printf("removed\n");
 	} else
 		printf("complete\n");
-	fflush(stdout);
+	(void)fflush(stdout);
 
 done:
 	relsesigs();
diff --git a/usr.bin/mail/send.c b/usr.bin/mail/send.c
index 9ffc05b..4d4e2de 100644
--- a/usr.bin/mail/send.c
+++ b/usr.bin/mail/send.c
@@ -57,29 +57,26 @@ static const char rcsid[] =
  */
 int
 sendmessage(mp, obuf, doign, prefix)
-	register struct message *mp;
+	struct message *mp;
 	FILE *obuf;
 	struct ignoretab *doign;
 	char *prefix;
 {
 	long count;
-	register FILE *ibuf;
-	char line[LINESIZE];
+	FILE *ibuf;
+	char *cp, *cp2, line[LINESIZE];
 	int ishead, infld, ignoring, dostat, firstline;
-	register char *cp, *cp2;
-	register int c;
-	int length;
-	int prefixlen;
+	int c, length, prefixlen;
 
 	/*
 	 * Compute the prefix string, without trailing whitespace
 	 */
-	if (prefix != NOSTR) {
+	if (prefix != NULL) {
 		cp2 = 0;
-		for (cp = prefix; *cp; cp++)
+		for (cp = prefix; *cp != '\0'; cp++)
 			if (*cp != ' ' && *cp != '\t')
 				cp2 = cp;
-		prefixlen = cp2 == 0 ? 0 : cp2 - prefix + 1;
+		prefixlen = cp2 == NULL ? 0 : cp2 - prefix + 1;
 	}
 	ibuf = setinput(mp);
 	count = mp->m_size;
@@ -125,7 +122,8 @@ sendmessage(mp, obuf, doign, prefix)
 			/*
 			 * Pick up the header field if we have one.
 			 */
-			for (cp = line; (c = *cp++) && c != ':' && !isspace(c);)
+			for (cp = line; (c = *cp++) != '\0' && c != ':' &&
+			    !isspace(c);)
 				;
 			cp2 = --cp;
 			while (isspace(*cp++))
@@ -142,7 +140,7 @@ sendmessage(mp, obuf, doign, prefix)
 				}
 				if (doign != ignoreall)
 					/* add blank line */
-					(void) putc('\n', obuf);
+					(void)putc('\n', obuf);
 				ishead = 0;
 				ignoring = 0;
 			} else {
@@ -150,7 +148,7 @@ sendmessage(mp, obuf, doign, prefix)
 				 * If it is an ignored field and
 				 * we care about such things, skip it.
 				 */
-				*cp2 = 0;	/* temporarily null terminate */
+				*cp2 = '\0';	/* temporarily null terminate */
 				if (doign && isign(line, doign))
 					ignoring = 1;
 				else if ((line[0] == 's' || line[0] == 'S') &&
@@ -176,16 +174,16 @@ sendmessage(mp, obuf, doign, prefix)
 			 * Strip trailing whitespace from prefix
 			 * if line is blank.
 			 */
-			if (prefix != NOSTR) {
+			if (prefix != NULL) {
 				if (length > 1)
 					fputs(prefix, obuf);
 				else
-					(void) fwrite(prefix, sizeof *prefix,
-							prefixlen, obuf);
+					(void)fwrite(prefix, sizeof(*prefix),
+					    prefixlen, obuf);
 			}
-			(void) fwrite(line, sizeof *line, length, obuf);
+			(void)fwrite(line, sizeof(*line), length, obuf);
 			if (ferror(obuf))
-				return -1;
+				return (-1);
 		}
 	}
 	/*
@@ -193,7 +191,7 @@ sendmessage(mp, obuf, doign, prefix)
 	 */
 	if (doign == ignoreall)
 		count--;		/* skip final blank line */
-	if (prefix != NOSTR)
+	if (prefix != NULL)
 		while (count > 0) {
 			if (fgets(line, sizeof(line), ibuf) == NULL) {
 				c = 0;
@@ -207,26 +205,26 @@ sendmessage(mp, obuf, doign, prefix)
 			if (c > 1)
 				fputs(prefix, obuf);
 			else
-				(void) fwrite(prefix, sizeof *prefix,
-						prefixlen, obuf);
-			(void) fwrite(line, sizeof *line, c, obuf);
+				(void)fwrite(prefix, sizeof(*prefix),
+				    prefixlen, obuf);
+			(void)fwrite(line, sizeof(*line), c, obuf);
 			if (ferror(obuf))
-				return -1;
+				return (-1);
 		}
 	else
 		while (count > 0) {
 			c = count < LINESIZE ? count : LINESIZE;
-			if ((c = fread(line, sizeof *line, c, ibuf)) <= 0)
+			if ((c = fread(line, sizeof(*line), c, ibuf)) <= 0)
 				break;
 			count -= c;
-			if (fwrite(line, sizeof *line, c, obuf) != c)
-				return -1;
+			if (fwrite(line, sizeof(*line), c, obuf) != c)
+				return (-1);
 		}
 	if (doign == ignoreall && c > 0 && line[c - 1] != '\n')
 		/* no final blank line */
 		if ((c = getc(ibuf)) != EOF && putc(c, obuf) == EOF)
-			return -1;
-	return 0;
+			return (-1);
+	return (0);
 }
 
 /*
@@ -234,21 +232,21 @@ sendmessage(mp, obuf, doign, prefix)
  */
 void
 statusput(mp, obuf, prefix)
-	register struct message *mp;
+	struct message *mp;
 	FILE *obuf;
 	char *prefix;
 {
 	char statout[3];
-	register char *cp = statout;
+	char *cp = statout;
 
 	if (mp->m_flag & MREAD)
 		*cp++ = 'R';
 	if ((mp->m_flag & MNEW) == 0)
 		*cp++ = 'O';
-	*cp = 0;
-	if (statout[0])
+	*cp = '\0';
+	if (statout[0] != '\0')
 		fprintf(obuf, "%sStatus: %s\n",
-			prefix == NOSTR ? "" : prefix, statout);
+			prefix == NULL ? "" : prefix, statout);
 }
 
 /*
@@ -268,9 +266,9 @@ mail(to, cc, bcc, smopts, subject, replyto)
 	head.h_bcc = bcc;
 	head.h_smopts = smopts;
 	head.h_replyto = replyto;
-	head.h_inreplyto = NOSTR;
+	head.h_inreplyto = NULL;
 	mail1(&head, 0);
-	return(0);
+	return (0);
 }
 
 
@@ -285,15 +283,15 @@ sendmail(str)
 	struct header head;
 
 	head.h_to = extract(str, GTO);
-	head.h_subject = NOSTR;
-	head.h_cc = NIL;
-	head.h_bcc = NIL;
-	head.h_smopts = NIL;
+	head.h_subject = NULL;
+	head.h_cc = NULL;
+	head.h_bcc = NULL;
+	head.h_smopts = NULL;
 	if ((head.h_replyto = getenv("REPLYTO")) == NULL)
-		head.h_replyto = NOSTR;
-	head.h_inreplyto = NOSTR;
+		head.h_replyto = NULL;
+	head.h_inreplyto = NULL;
 	mail1(&head, 0);
-	return(0);
+	return (0);
 }
 
 /*
@@ -317,16 +315,16 @@ mail1(hp, printheaders)
 	 */
 	if ((mtf = collect(hp, printheaders)) == NULL)
 		return;
-	if (value("interactive") != NOSTR) {
-		if (value("askcc") != NOSTR)
+	if (value("interactive") != NULL) {
+		if (value("askcc") != NULL)
 			grabh(hp, GCC);
 		else {
 			printf("EOT\n");
-			(void) fflush(stdout);
+			(void)fflush(stdout);
 		}
 	}
 	if (fsize(mtf) == 0) {
-		if (hp->h_subject == NOSTR)
+		if (hp->h_subject == NULL)
 			printf("No message, no subject; hope that's ok\n");
 		else
 			printf("Null message body; hope that's ok\n");
@@ -338,7 +336,7 @@ mail1(hp, printheaders)
 	 */
 	senderr = 0;
 	to = usermap(cat(hp->h_bcc, cat(hp->h_to, hp->h_cc)));
-	if (to == NIL) {
+	if (to == NULL) {
 		printf("No recipients specified\n");
 		senderr++;
 	}
@@ -362,13 +360,13 @@ mail1(hp, printheaders)
 		char **t;
 
 		printf("Sendmail arguments:");
-		for (t = namelist; *t != NOSTR; t++)
+		for (t = namelist; *t != NULL; t++)
 			printf(" \"%s\"", *t);
 		printf("\n");
 		goto out;
 	}
-	if ((cp = value("record")) != NOSTR)
-		(void) savemail(expand(cp), mtf);
+	if ((cp = value("record")) != NULL)
+		(void)savemail(expand(cp), mtf);
 	/*
 	 * Fork, set up the temporary mail file as standard
 	 * input for "mail", and exec with the user list we generated
@@ -384,7 +382,7 @@ mail1(hp, printheaders)
 		prepare_child(sigmask(SIGHUP)|sigmask(SIGINT)|sigmask(SIGQUIT)|
 			sigmask(SIGTSTP)|sigmask(SIGTTIN)|sigmask(SIGTTOU),
 			fileno(mtf), -1);
-		if ((cp = value("sendmail")) != NOSTR)
+		if ((cp = value("sendmail")) != NULL)
 			cp = expand(cp);
 		else
 			cp = _PATH_SENDMAIL;
@@ -392,12 +390,12 @@ mail1(hp, printheaders)
 		warn("%s", cp);
 		_exit(1);
 	}
-	if (value("verbose") != NOSTR)
-		(void) wait_child(pid);
+	if (value("verbose") != NULL)
+		(void)wait_child(pid);
 	else
 		free_child(pid);
 out:
-	(void) Fclose(mtf);
+	(void)Fclose(mtf);
 }
 
 /*
@@ -409,21 +407,21 @@ fixhead(hp, tolist)
 	struct header *hp;
 	struct name *tolist;
 {
-	register struct name *np;
+	struct name *np;
 
-	hp->h_to = NIL;
-	hp->h_cc = NIL;
-	hp->h_bcc = NIL;
-	for (np = tolist; np != NIL; np = np->n_flink)
+	hp->h_to = NULL;
+	hp->h_cc = NULL;
+	hp->h_bcc = NULL;
+	for (np = tolist; np != NULL; np = np->n_flink)
 		if ((np->n_type & GMASK) == GTO)
 			hp->h_to =
-				cat(hp->h_to, nalloc(np->n_name, np->n_type));
+			    cat(hp->h_to, nalloc(np->n_name, np->n_type));
 		else if ((np->n_type & GMASK) == GCC)
 			hp->h_cc =
-				cat(hp->h_cc, nalloc(np->n_name, np->n_type));
+			    cat(hp->h_cc, nalloc(np->n_name, np->n_type));
 		else if ((np->n_type & GMASK) == GBCC)
 			hp->h_bcc =
-				cat(hp->h_bcc, nalloc(np->n_name, np->n_type));
+			    cat(hp->h_bcc, nalloc(np->n_name, np->n_type));
 }
 
 /*
@@ -435,48 +433,48 @@ infix(hp, fi)
 	struct header *hp;
 	FILE *fi;
 {
-	register FILE *nfo, *nfi;
-	register int c;
-	int fd;
+	FILE *nfo, *nfi;
+	int c, fd;
 	char tempname[PATHSIZE];
 
-	snprintf(tempname, sizeof(tempname), "%s/mail.RsXXXXXXXXXX", tmpdir);
+	(void)snprintf(tempname, sizeof(tempname),
+	    "%s/mail.RsXXXXXXXXXX", tmpdir);
 	if ((fd = mkstemp(tempname)) == -1 ||
 	    (nfo = Fdopen(fd, "w")) == NULL) {
 		warn("%s", tempname);
-		return(fi);
+		return (fi);
 	}
 	if ((nfi = Fopen(tempname, "r")) == NULL) {
 		warn("%s", tempname);
-		(void) Fclose(nfo);
-		(void) rm(tempname);
-		return(fi);
+		(void)Fclose(nfo);
+		(void)rm(tempname);
+		return (fi);
 	}
-	(void) rm(tempname);
-	(void) puthead(hp, nfo,
-		       GTO|GSUBJECT|GCC|GBCC|GREPLYTO|GINREPLYTO|GNL|GCOMMA);
+	(void)rm(tempname);
+	(void)puthead(hp, nfo,
+	    GTO|GSUBJECT|GCC|GBCC|GREPLYTO|GINREPLYTO|GNL|GCOMMA);
 	c = getc(fi);
 	while (c != EOF) {
-		(void) putc(c, nfo);
+		(void)putc(c, nfo);
 		c = getc(fi);
 	}
 	if (ferror(fi)) {
 		warnx("read");
 		rewind(fi);
-		return(fi);
+		return (fi);
 	}
-	(void) fflush(nfo);
+	(void)fflush(nfo);
 	if (ferror(nfo)) {
 		warn("%s", tempname);
-		(void) Fclose(nfo);
-		(void) Fclose(nfi);
+		(void)Fclose(nfo);
+		(void)Fclose(nfi);
 		rewind(fi);
-		return(fi);
+		return (fi);
 	}
-	(void) Fclose(nfo);
-	(void) Fclose(fi);
+	(void)Fclose(nfo);
+	(void)Fclose(fi);
 	rewind(nfi);
-	return(nfi);
+	return (nfi);
 }
 
 /*
@@ -489,24 +487,24 @@ puthead(hp, fo, w)
 	FILE *fo;
 	int w;
 {
-	register int gotcha;
+	int gotcha;
 
 	gotcha = 0;
-	if (hp->h_to != NIL && w & GTO)
+	if (hp->h_to != NULL && w & GTO)
 		fmt("To:", hp->h_to, fo, w&GCOMMA), gotcha++;
-	if (hp->h_subject != NOSTR && w & GSUBJECT)
+	if (hp->h_subject != NULL && w & GSUBJECT)
 		fprintf(fo, "Subject: %s\n", hp->h_subject), gotcha++;
-	if (hp->h_cc != NIL && w & GCC)
+	if (hp->h_cc != NULL && w & GCC)
 		fmt("Cc:", hp->h_cc, fo, w&GCOMMA), gotcha++;
-	if (hp->h_bcc != NIL && w & GBCC)
+	if (hp->h_bcc != NULL && w & GBCC)
 		fmt("Bcc:", hp->h_bcc, fo, w&GCOMMA), gotcha++;
-	if (hp->h_replyto != NOSTR && w & GREPLYTO)
+	if (hp->h_replyto != NULL && w & GREPLYTO)
 		fprintf(fo, "Reply-To: %s\n", hp->h_replyto), gotcha++;
-	if (hp->h_inreplyto != NOSTR && w & GINREPLYTO)
+	if (hp->h_inreplyto != NULL && w & GINREPLYTO)
 		fprintf(fo, "In-Reply-To: <%s>\n", hp->h_inreplyto), gotcha++;
 	if (gotcha && w & GNL)
-		(void) putc('\n', fo);
-	return(0);
+		(void)putc('\n', fo);
+	return (0);
 }
 
 /*
@@ -514,33 +512,33 @@ puthead(hp, fo, w)
  */
 void
 fmt(str, np, fo, comma)
-	char *str;
-	register struct name *np;
+	const char *str;
+	struct name *np;
 	FILE *fo;
 	int comma;
 {
-	register col, len;
+	int col, len;
 
 	comma = comma ? 1 : 0;
 	col = strlen(str);
 	if (col)
 		fputs(str, fo);
-	for (; np != NIL; np = np->n_flink) {
-		if (np->n_flink == NIL)
+	for (; np != NULL; np = np->n_flink) {
+		if (np->n_flink == NULL)
 			comma = 0;
 		len = strlen(np->n_name);
 		col++;		/* for the space */
 		if (col + len + comma > 72 && col > 4) {
-			fputs("\n    ", fo);
+			fprintf(fo, "\n    ");
 			col = 4;
 		} else
-			putc(' ', fo);
+			fprintf(fo, " ");
 		fputs(np->n_name, fo);
 		if (comma)
-			putc(',', fo);
+			fprintf(fo, ",");
 		col += len + comma;
 	}
-	putc('\n', fo);
+	fprintf(fo, "\n");
 }
 
 /*
@@ -551,27 +549,26 @@ fmt(str, np, fo, comma)
 int
 savemail(name, fi)
 	char name[];
-	register FILE *fi;
+	FILE *fi;
 {
-	register FILE *fo;
+	FILE *fo;
 	char buf[BUFSIZ];
-	register i;
-	time_t now, time();
-	char *ctime();
+	int i;
+	time_t now;
 
 	if ((fo = Fopen(name, "a")) == NULL) {
 		warn("%s", name);
 		return (-1);
 	}
-	(void) time(&now);
+	(void)time(&now);
 	fprintf(fo, "From %s %s", myname, ctime(&now));
-	while ((i = fread(buf, 1, sizeof buf, fi)) > 0)
-		(void) fwrite(buf, 1, i, fo);
-	(void) putc('\n', fo);
-	(void) fflush(fo);
+	while ((i = fread(buf, 1, sizeof(buf), fi)) > 0)
+		(void)fwrite(buf, 1, i, fo);
+	fprintf(fo, "\n");
+	(void)fflush(fo);
 	if (ferror(fo))
 		warn("%s", name);
-	(void) Fclose(fo);
+	(void)Fclose(fo);
 	rewind(fi);
 	return (0);
 }
diff --git a/usr.bin/mail/strings.c b/usr.bin/mail/strings.c
index 08626d9..684a6d1 100644
--- a/usr.bin/mail/strings.c
+++ b/usr.bin/mail/strings.c
@@ -62,17 +62,16 @@ char *
 salloc(size)
 	int size;
 {
-	register char *t;
-	register int s;
-	register struct strings *sp;
-	int index;
+	char *t;
+	int s, index;
+	struct strings *sp;
 
 	s = size;
-	s += (sizeof (char *) - 1);
-	s &= ~(sizeof (char *) - 1);
+	s += (sizeof(char *) - 1);
+	s &= ~(sizeof(char *) - 1);
 	index = 0;
 	for (sp = &stringdope[0]; sp < &stringdope[NSPACE]; sp++) {
-		if (sp->s_topFree == NOSTR && (STRINGSIZE << index) >= s)
+		if (sp->s_topFree == NULL && (STRINGSIZE << index) >= s)
 			break;
 		if (sp->s_nleft >= s)
 			break;
@@ -80,9 +79,9 @@ salloc(size)
 	}
 	if (sp >= &stringdope[NSPACE])
 		errx(1, "String too large");
-	if (sp->s_topFree == NOSTR) {
+	if (sp->s_topFree == NULL) {
 		index = sp - &stringdope[0];
-		if ((sp->s_topFree = malloc(STRINGSIZE << index)) == NOSTR)
+		if ((sp->s_topFree = malloc(STRINGSIZE << index)) == NULL)
 			err(1, "No room for space %d", index);
 		sp->s_nextFree = sp->s_topFree;
 		sp->s_nleft = STRINGSIZE << index;
@@ -90,7 +89,7 @@ salloc(size)
 	sp->s_nleft -= s;
 	t = sp->s_nextFree;
 	sp->s_nextFree += s;
-	return(t);
+	return (t);
 }
 
 /*
@@ -101,14 +100,14 @@ salloc(size)
 void
 sreset()
 {
-	register struct strings *sp;
-	register int index;
+	struct strings *sp;
+	int index;
 
 	if (noreset)
 		return;
 	index = 0;
 	for (sp = &stringdope[0]; sp < &stringdope[NSPACE]; sp++) {
-		if (sp->s_topFree == NOSTR)
+		if (sp->s_topFree == NULL)
 			continue;
 		sp->s_nextFree = sp->s_topFree;
 		sp->s_nleft = STRINGSIZE << index;
@@ -123,8 +122,8 @@ sreset()
 void
 spreserve()
 {
-	register struct strings *sp;
+	struct strings *sp;
 
 	for (sp = &stringdope[0]; sp < &stringdope[NSPACE]; sp++)
-		sp->s_topFree = NOSTR;
+		sp->s_topFree = NULL;
 }
diff --git a/usr.bin/mail/temp.c b/usr.bin/mail/temp.c
index dc51c38..a3ced98 100644
--- a/usr.bin/mail/temp.c
+++ b/usr.bin/mail/temp.c
@@ -53,7 +53,7 @@ char	*tmpdir;
 void
 tinit()
 {
-	register char *cp;
+	char *cp;
 
 	if ((tmpdir = getenv("TMPDIR")) == NULL || *tmpdir == '\0')
 		tmpdir = _PATH_TMP;
@@ -70,23 +70,23 @@ tinit()
 	 * It's okay to call savestr in here because main will
 	 * do a spreserve() after us.
 	 */
-	if (myname != NOSTR) {
+	if (myname != NULL) {
 		if (getuserid(myname) < 0)
 			errx(1, "\"%s\" is not a user of this system", myname);
 	} else {
-		if ((cp = username()) == NOSTR) {
+		if ((cp = username()) == NULL) {
 			myname = "ubluit";
 			if (rcvmode)
 				errx(1, "Who are you!?");
 		} else
 			myname = savestr(cp);
 	}
-	if ((cp = getenv("HOME")) == NOSTR || *cp == '\0' ||
+	if ((cp = getenv("HOME")) == NULL || *cp == '\0' ||
 	    strlen(cp) >= PATHSIZE)
 		homedir = NULL;
 	else
 		homedir = savestr(cp);
 	if (debug)
 		printf("user = %s, homedir = %s\n", myname,
-		       homedir ? homedir : "NONE");
+		    homedir ? homedir : "NONE");
 }
diff --git a/usr.bin/mail/tty.c b/usr.bin/mail/tty.c
index c4f37fe..687ce59 100644
--- a/usr.bin/mail/tty.c
+++ b/usr.bin/mail/tty.c
@@ -74,7 +74,6 @@ grabh(hp, gflags)
 	sig_t savettou;
 	sig_t savettin;
 	int errs;
-	void ttyint();
 
 	savetstp = signal(SIGTSTP, SIG_DFL);
 	savettou = signal(SIGTTOU, SIG_DFL);
@@ -85,7 +84,7 @@ grabh(hp, gflags)
 #endif
 	if (tcgetattr(fileno(stdin), &tio) < 0) {
 		warn("tcgetattr(stdin)");
-		return(-1);
+		return (-1);
 	}
 	c_erase = tio.c_cc[VERASE];
 	c_kill = tio.c_cc[VKILL];
@@ -93,9 +92,9 @@ grabh(hp, gflags)
 	tio.c_cc[VERASE] = 0;
 	tio.c_cc[VKILL] = 0;
 	if ((saveint = signal(SIGINT, SIG_IGN)) == SIG_DFL)
-		signal(SIGINT, SIG_DFL);
+		(void)signal(SIGINT, SIG_DFL);
 	if ((savequit = signal(SIGQUIT, SIG_IGN)) == SIG_DFL)
-		signal(SIGQUIT, SIG_DFL);
+		(void)signal(SIGQUIT, SIG_DFL);
 #else
 	if (setjmp(intjmp))
 		goto out;
@@ -103,7 +102,7 @@ grabh(hp, gflags)
 #endif
 	if (gflags & GTO) {
 #ifndef TIOCSTI
-		if (!ttyset && hp->h_to != NIL)
+		if (!ttyset && hp->h_to != NULL)
 			ttyset++, tcsetattr(fileno(stdin), TCSADRAIN, &tio);
 #endif
 		hp->h_to =
@@ -111,14 +110,14 @@ grabh(hp, gflags)
 	}
 	if (gflags & GSUBJECT) {
 #ifndef TIOCSTI
-		if (!ttyset && hp->h_subject != NOSTR)
+		if (!ttyset && hp->h_subject != NULL)
 			ttyset++, tcsetattr(fileno(stdin), TCSADRAIN, &tio);
 #endif
 		hp->h_subject = readtty("Subject: ", hp->h_subject);
 	}
 	if (gflags & GCC) {
 #ifndef TIOCSTI
-		if (!ttyset && hp->h_cc != NIL)
+		if (!ttyset && hp->h_cc != NULL)
 			ttyset++, tcsetattr(fileno(stdin), TCSADRAIN, &tio);
 #endif
 		hp->h_cc =
@@ -126,25 +125,25 @@ grabh(hp, gflags)
 	}
 	if (gflags & GBCC) {
 #ifndef TIOCSTI
-		if (!ttyset && hp->h_bcc != NIL)
+		if (!ttyset && hp->h_bcc != NULL)
 			ttyset++, tcsetattr(fileno(stdin), TCSADRAIN, &tio);
 #endif
 		hp->h_bcc =
 			extract(readtty("Bcc: ", detract(hp->h_bcc, 0)), GBCC);
 	}
 out:
-	signal(SIGTSTP, savetstp);
-	signal(SIGTTOU, savettou);
-	signal(SIGTTIN, savettin);
+	(void)signal(SIGTSTP, savetstp);
+	(void)signal(SIGTTOU, savettou);
+	(void)signal(SIGTTIN, savettin);
 #ifndef TIOCSTI
 	tio.c_cc[VERASE] = c_erase;
 	tio.c_cc[VKILL] = c_kill;
 	if (ttyset)
 		tcsetattr(fileno(stdin), TCSADRAIN, &tio);
-	signal(SIGQUIT, savequit);
+	(void)signal(SIGQUIT, savequit);
 #endif
-	signal(SIGINT, saveint);
-	return(errs);
+	(void)signal(SIGINT, saveint);
+	return (errs);
 }
 
 /*
@@ -156,29 +155,29 @@ out:
 
 char *
 readtty(pr, src)
-	char pr[], src[];
+	const char *pr;
+	char src[];
 {
 	char ch, canonb[BUFSIZ];
 	int c;
-	register char *cp, *cp2;
-	void ttystop();
+	char *cp, *cp2;
 
 	fputs(pr, stdout);
-	fflush(stdout);
-	if (src != NOSTR && strlen(src) > BUFSIZ - 2) {
+	(void)fflush(stdout);
+	if (src != NULL && strlen(src) > BUFSIZ - 2) {
 		printf("too long to edit\n");
-		return(src);
+		return (src);
 	}
 #ifndef TIOCSTI
-	if (src != NOSTR)
+	if (src != NULL)
 		strlcpy(canonb, src, sizeof(canonb));
 	else
 		*canonb = '\0';
 	fputs(canonb, stdout);
-	fflush(stdout);
+	(void)fflush(stdout);
 #else
-	cp = src == NOSTR ? "" : src;
-	while (c = *cp++) {
+	cp = src == NULL ? "" : src;
+	while ((c = *cp++) != '\0') {
 		if (c == c_erase || c == c_kill) {
 			ch = '\\';
 			ioctl(0, TIOCSTI, &ch);
@@ -195,9 +194,9 @@ readtty(pr, src)
 	cp2 = cp;
 	if (setjmp(rewrite))
 		goto redo;
-	signal(SIGTSTP, ttystop);
-	signal(SIGTTOU, ttystop);
-	signal(SIGTTIN, ttystop);
+	(void)signal(SIGTSTP, ttystop);
+	(void)signal(SIGTTOU, ttystop);
+	(void)signal(SIGTTIN, ttystop);
 	clearerr(stdin);
 	while (cp2 < canonb + BUFSIZ) {
 		c = getc(stdin);
@@ -205,22 +204,22 @@ readtty(pr, src)
 			break;
 		*cp2++ = c;
 	}
-	*cp2 = 0;
-	signal(SIGTSTP, SIG_DFL);
-	signal(SIGTTOU, SIG_DFL);
-	signal(SIGTTIN, SIG_DFL);
+	*cp2 = '\0';
+	(void)signal(SIGTSTP, SIG_DFL);
+	(void)signal(SIGTTOU, SIG_DFL);
+	(void)signal(SIGTTIN, SIG_DFL);
 	if (c == EOF && ferror(stdin)) {
 redo:
-		cp = strlen(canonb) > 0 ? canonb : NOSTR;
+		cp = strlen(canonb) > 0 ? canonb : NULL;
 		clearerr(stdin);
-		return(readtty(pr, cp));
+		return (readtty(pr, cp));
 	}
 #ifndef TIOCSTI
-	if (cp == NOSTR || *cp == '\0')
-		return(src);
+	if (cp == NULL || *cp == '\0')
+		return (src);
 	cp2 = cp;
 	if (!ttyset)
-		return(strlen(canonb) > 0 ? savestr(canonb) : NOSTR);
+		return (strlen(canonb) > 0 ? savestr(canonb) : NULL);
 	while (*cp != '\0') {
 		c = *cp++;
 		if (c == c_erase) {
@@ -248,8 +247,8 @@ redo:
 	*cp2 = '\0';
 #endif
 	if (equal("", canonb))
-		return(NOSTR);
-	return(savestr(canonb));
+		return (NULL);
+	return (savestr(canonb));
 }
 
 /*
@@ -261,10 +260,10 @@ ttystop(s)
 {
 	sig_t old_action = signal(s, SIG_DFL);
 
-	sigsetmask(sigblock(0) & ~sigmask(s));
-	kill(0, s);
-	sigblock(sigmask(s));
-	signal(s, old_action);
+	(void)sigsetmask(sigblock(0) & ~sigmask(s));
+	(void)kill(0, s);
+	(void)sigblock(sigmask(s));
+	(void)signal(s, old_action);
 	longjmp(rewrite, 1);
 }
 
diff --git a/usr.bin/mail/v7.local.c b/usr.bin/mail/v7.local.c
index 03f2775..3007a49 100644
--- a/usr.bin/mail/v7.local.c
+++ b/usr.bin/mail/v7.local.c
@@ -60,7 +60,7 @@ findmail(user, buf, buflen)
 	char *user, *buf;
 	int buflen;
 {
-	char	*tmp = getenv("MAIL");
+	char *tmp = getenv("MAIL");
 
 	if (tmp == NULL)
 		(void)snprintf(buf, buflen, "%s/%s", _PATH_MAILDIR, user);
@@ -75,8 +75,8 @@ void
 demail()
 {
 
-	if (value("keep") != NOSTR || rm(mailname) < 0)
-		close(open(mailname, O_CREAT | O_TRUNC | O_WRONLY, 0600));
+	if (value("keep") != NULL || rm(mailname) < 0)
+		(void)close(open(mailname, O_CREAT | O_TRUNC | O_WRONLY, 0600));
 }
 
 /*
@@ -88,12 +88,12 @@ username()
 	char *np;
 	uid_t uid;
 
-	if ((np = getenv("USER")) != NOSTR)
-		return np;
-	if ((np = getenv("LOGNAME")) != NOSTR)
-		return np;
-	if ((np = getname(uid = getuid())) != NOSTR)
-		return np;
+	if ((np = getenv("USER")) != NULL)
+		return (np);
+	if ((np = getenv("LOGNAME")) != NULL)
+		return (np);
+	if ((np = getname(uid = getuid())) != NULL)
+		return (np);
 	printf("Cannot associate a name with uid %u\n", (unsigned)uid);
-	return NOSTR;
+	return (NULL);
 }
diff --git a/usr.bin/mail/vars.c b/usr.bin/mail/vars.c
index 5d09d0f..fdf3f40 100644
--- a/usr.bin/mail/vars.c
+++ b/usr.bin/mail/vars.c
@@ -53,15 +53,15 @@ static const char rcsid[] =
  */
 void
 assign(name, value)
-	char name[], value[];
+	const char *name, *value;
 {
-	register struct var *vp;
-	register int h;
+	struct var *vp;
+	int h;
 
 	h = hash(name);
 	vp = lookup(name);
-	if (vp == NOVAR) {
-		vp = (struct var *) calloc(sizeof *vp, 1);
+	if (vp == NULL) {
+		vp = calloc(sizeof(*vp), 1);
 		vp->v_name = vcopy(name);
 		vp->v_link = variables[h];
 		variables[h] = vp;
@@ -80,8 +80,8 @@ void
 vfree(cp)
 	char *cp;
 {
-	if (*cp)
-		free(cp);
+	if (*cp != '\0')
+		(void)free(cp);
 }
 
 /*
@@ -91,18 +91,18 @@ vfree(cp)
 
 char *
 vcopy(str)
-	char str[];
+	const char *str;
 {
 	char *new;
 	unsigned len;
 
 	if (*str == '\0')
-		return "";
+		return ("");
 	len = strlen(str) + 1;
 	if ((new = malloc(len)) == NULL)
 		err(1, "Out of memory");
-	bcopy(str, new, (int) len);
-	return new;
+	bcopy(str, new, (int)len);
+	return (new);
 }
 
 /*
@@ -112,13 +112,13 @@ vcopy(str)
 
 char *
 value(name)
-	char name[];
+	const char *name;
 {
-	register struct var *vp;
+	struct var *vp;
 
-	if ((vp = lookup(name)) == NOVAR)
-		return(getenv(name));
-	return(vp->v_value);
+	if ((vp = lookup(name)) == NULL)
+		return (getenv(name));
+	return (vp->v_value);
 }
 
 /*
@@ -128,14 +128,14 @@ value(name)
 
 struct var *
 lookup(name)
-	register char name[];
+	const char *name;
 {
-	register struct var *vp;
+	struct var *vp;
 
-	for (vp = variables[hash(name)]; vp != NOVAR; vp = vp->v_link)
+	for (vp = variables[hash(name)]; vp != NULL; vp = vp->v_link)
 		if (*vp->v_name == *name && equal(vp->v_name, name))
-			return(vp);
-	return(NOVAR);
+			return (vp);
+	return (NULL);
 }
 
 /*
@@ -144,14 +144,14 @@ lookup(name)
 
 struct grouphead *
 findgroup(name)
-	register char name[];
+	char name[];
 {
-	register struct grouphead *gh;
+	struct grouphead *gh;
 
-	for (gh = groups[hash(name)]; gh != NOGRP; gh = gh->g_link)
+	for (gh = groups[hash(name)]; gh != NULL; gh = gh->g_link)
 		if (*gh->g_name == *name && equal(gh->g_name, name))
-			return(gh);
-	return(NOGRP);
+			return (gh);
+	return (NULL);
 }
 
 /*
@@ -161,17 +161,17 @@ void
 printgroup(name)
 	char name[];
 {
-	register struct grouphead *gh;
-	register struct group *gp;
+	struct grouphead *gh;
+	struct group *gp;
 
-	if ((gh = findgroup(name)) == NOGRP) {
+	if ((gh = findgroup(name)) == NULL) {
 		printf("\"%s\": not a group\n", name);
 		return;
 	}
 	printf("%s\t", gh->g_name);
-	for (gp = gh->g_list; gp != NOGE; gp = gp->ge_link)
+	for (gp = gh->g_list; gp != NULL; gp = gp->ge_link)
 		printf(" %s", gp->ge_name);
-	putchar('\n');
+	printf("\n");
 }
 
 /*
@@ -180,11 +180,11 @@ printgroup(name)
  */
 int
 hash(name)
-	register char *name;
+	const char *name;
 {
-	register h = 0;
+	int h = 0;
 
-	while (*name) {
+	while (*name != '\0') {
 		h <<= 2;
 		h += *name++;
 	}
diff --git a/usr.bin/mail/version.c b/usr.bin/mail/version.c
index f3d9ab8..58f5638 100644
--- a/usr.bin/mail/version.c
+++ b/usr.bin/mail/version.c
@@ -43,4 +43,4 @@ static const char rcsid[] =
  * Just keep track of the date/sid of this version of Mail.
  * Load this file first to get a "total" Mail version.
  */
-char	*version = "8.1 6/6/93";
+const char	*version = "8.1 6/6/93";