1 files changed, 106 insertions, 0 deletions
diff --git a/share/doc/psd/20.ipctut/strchkread.c b/share/doc/psd/20.ipctut/strchkread.c
new file mode 100644
index 0000000..dcab1fc
--- /dev/null
+++ b/share/doc/psd/20.ipctut/strchkread.c
@@ -0,0 +1,106 @@
+.\" Copyright (c) 1986, 1993
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"	This product includes software developed by the University of
+.\"	California, Berkeley and its contributors.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"	@(#)strchkread.c	8.1 (Berkeley) 6/8/93
+.\"
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <netinet/in.h>
+#include <netdb.h>
+#include <stdio.h>
+#define TRUE 1
+
+/*
+ * This program uses select() to check that someone is trying to connect
+ * before calling accept(). 
+ */
+
+main()
+{
+	int sock, length;
+	struct sockaddr_in server;
+	int msgsock;
+	char buf[1024];
+	int rval;
+	fd_set ready;
+	struct timeval to;
+
+	/* Create socket */
+	sock = socket(AF_INET, SOCK_STREAM, 0);
+	if (sock < 0) {
+		perror("opening stream socket");
+		exit(1);
+	}
+	/* Name socket using wildcards */
+	server.sin_family = AF_INET;
+	server.sin_addr.s_addr = INADDR_ANY;
+	server.sin_port = 0;
+	if (bind(sock, &server, sizeof(server))) {
+		perror("binding stream socket");
+		exit(1);
+	}
+	/* Find out assigned port number and print it out */
+	length = sizeof(server);
+	if (getsockname(sock, &server, &length)) {
+		perror("getting socket name");
+		exit(1);
+	}
+	printf("Socket has port #%d\en", ntohs(server.sin_port));
+
+	/* Start accepting connections */
+	listen(sock, 5);
+	do {
+		FD_ZERO(&ready);
+		FD_SET(sock, &ready);
+		to.tv_sec = 5;
+		if (select(sock + 1, &ready, 0, 0, &to) < 0) {
+			perror("select");
+			continue;
+		}
+		if (FD_ISSET(sock, &ready)) {
+			msgsock = accept(sock, (struct sockaddr *)0, (int *)0);
+			if (msgsock == -1)
+				perror("accept");
+			else do {
+				bzero(buf, sizeof(buf));
+				if ((rval = read(msgsock, buf, 1024)) < 0)
+					perror("reading stream message");
+				else if (rval == 0)
+					printf("Ending connection\en");
+				else
+					printf("-->%s\en", buf);
+			} while (rval > 0);
+			close(msgsock);
+		} else
+			printf("Do something else\en");
+	} while (TRUE);
+}