1 files changed, 93 insertions, 0 deletions
diff --git a/reference/C/CONTRIB/OR_USING_C/12.3.c b/reference/C/CONTRIB/OR_USING_C/12.3.c
new file mode 100644
index 0000000..50b755c
--- /dev/null
+++ b/reference/C/CONTRIB/OR_USING_C/12.3.c
@@ -0,0 +1,93 @@
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netdb.h>
+#include <stdio.h>
+
+#define BUFSZ       256
+#define SERVICE     "daytime"
+
+main(argc, argv)
+int argc;
+char **argv;
+{
+    int s, n, len;
+    char buf[BUFSZ];
+    struct hostent *hp;
+    struct servent *sp;
+    struct sockaddr_in sin;
+
+    /*
+     * Get a datagram socket in the Internet
+     * domain.
+     */
+    if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
+        perror("socket");
+        exit(1);
+    }
+
+    /*
+     * Look up the port number of the service.
+     */
+    if ((sp = getservbyname(SERVICE, "udp")) == NULL) {
+        fprintf(stderr, "%s/udp: unknown service.\n", SERVICE);
+        exit(1);
+    }
+
+    /*
+     * For each host on the command line...
+     */
+    while (--argc) {
+        /*
+         * Look up the network number of
+         * the host.
+         */
+        if ((hp = gethostbyname(*++argv)) == NULL) {
+            fprintf(stderr, "%s: host unknown.\n", *argv);
+            continue;
+        }
+
+        /*
+         * Build the address of the server on
+         * the remote machine.
+         */
+        sin.sin_family = AF_INET;
+        sin.sin_port = sp->s_port;
+        bcopy(hp->h_addr, &sin.sin_addr, hp->h_length);
+
+        /*
+         * Print the name of the host.
+         */
+        printf("%s: ", *argv);
+        fflush(stdout);
+
+        /*
+         * Send a datagram to the server.
+         */
+        if (sendto(s, buf, BUFSZ, 0, &sin, sizeof(sin)) < 0) {
+            perror("sendto");
+            continue;
+        }
+
+        /*
+         * Receive a datagram back.
+         */
+        len = sizeof(sin);
+        n = recvfrom(s, buf, sizeof(buf), 0, &sin, &len);
+
+        if (n < 0) {
+            perror("recvfrom");
+            continue;
+        }
+
+        /*
+         * Print the datagram.
+         */
+        buf[n] = NULL;
+        printf("%s\n", buf);
+    }
+
+    close(s);
+    exit(0);
+}
+