3 files changed, 8 insertions, 11 deletions
diff --git a/lib/libc/resolv/mtctxres.c b/lib/libc/resolv/mtctxres.c
index f02a7f5..c2aea38 100644
--- a/lib/libc/resolv/mtctxres.c
+++ b/lib/libc/resolv/mtctxres.c
@@ -75,7 +75,7 @@ __res_init_ctx(void) {
 		return (0);
 	}
 
-	if ((mt = malloc(sizeof (mtctxres_t))) == 0) {
+	if ((mt = malloc(sizeof(mtctxres_t))) == NULL) {
 		errno = ENOMEM;
 		return (-1);
 	}
@@ -94,10 +94,7 @@ __res_init_ctx(void) {
 static void
 __res_destroy_ctx(void *value) {
 
-	mtctxres_t	*mt = (mtctxres_t *)value;
-
-	if (mt != 0)
-		free(mt);
+	free(value);
 }
 #endif
 
@@ -130,9 +127,9 @@ ___mtctxres(void) {
 	 * that fails return a global context.
 	 */
 	if (mt_key_initialized) {
-		if (((mt = pthread_getspecific(key)) != 0) ||
+		if (((mt = pthread_getspecific(key)) != NULL) ||
 		    (__res_init_ctx() == 0 &&
-		     (mt = pthread_getspecific(key)) != 0)) {
+		     (mt = pthread_getspecific(key)) != NULL)) {
 			return (mt);
 		}
 	}
diff --git a/lib/libc/resolv/res_init.c b/lib/libc/resolv/res_init.c
index 715b654..76ad311 100644
--- a/lib/libc/resolv/res_init.c
+++ b/lib/libc/resolv/res_init.c
@@ -315,7 +315,7 @@ __res_vinit(res_state statp, int preinit) {
 		while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
 			cp++;
 		*cp = '\0';
-		*pp++ = 0;
+		*pp++ = NULL;
 	}
 
 #define	MATCH(line, name) \
@@ -391,7 +391,7 @@ __res_vinit(res_state statp, int preinit) {
 		    while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 			    cp++;
 		    *cp = '\0';
-		    *pp++ = 0;
+		    *pp++ = NULL;
 		    havesearch = 1;
 		    continue;
 		}
diff --git a/lib/libc/resolv/res_mkupdate.c b/lib/libc/resolv/res_mkupdate.c
index 5c5858d..45667c4 100644
--- a/lib/libc/resolv/res_mkupdate.c
+++ b/lib/libc/resolv/res_mkupdate.c
@@ -1175,7 +1175,7 @@ res_protocolname(int num) {
 	if (protolist == (struct valuelist *)0)
 		res_buildprotolist();
 	pp = cgetprotobynumber(num);
-	if (pp == 0)  {
+	if (pp == NULL)  {
 		(void) sprintf(number, "%d", num);
 		return (number);
 	}
@@ -1190,7 +1190,7 @@ res_servicename(u_int16_t port, const char *proto) {	/*%< Host byte order. */
 	if (servicelist == (struct valuelist *)0)
 		res_buildservicelist();
 	ss = cgetservbyport(htons(port), proto);
-	if (ss == 0)  {
+	if (ss == NULL)  {
 		(void) sprintf(number, "%d", port);
 		return (number);
 	}