1/* Example of Reading Datagrams
2 Copyright (C) 1991-2022 Free Software Foundation, Inc.
3
4 This program is free software; you can redistribute it and/or
5 modify it under the terms of the GNU General Public License
6 as published by the Free Software Foundation; either version 2
7 of the License, or (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, see <https://www.gnu.org/licenses/>.
16*/
17
18#include <stdio.h>
19#include <errno.h>
20#include <unistd.h>
21#include <stdlib.h>
22#include <sys/socket.h>
23#include <sys/un.h>
24
25#define SERVER "/tmp/serversocket"
26#define CLIENT "/tmp/mysocket"
27#define MAXMSG 512
28#define MESSAGE "Yow!!! Are we having fun yet?!?"
29
30int
31main (void)
32{
33 extern int make_named_socket (const char *name);
34 int sock;
35 char message[MAXMSG];
36 struct sockaddr_un name;
37 size_t size;
38 int nbytes;
39
40 /* Make the socket. */
41 sock = make_named_socket (CLIENT);
42
43 /* Initialize the server socket address. */
44 name.sun_family = AF_LOCAL;
45 strcpy (name.sun_path, SERVER);
46 size = strlen (name.sun_path) + sizeof (name.sun_family);
47
48 /* Send the datagram. */
49 nbytes = sendto (fd: sock, MESSAGE, n: strlen (MESSAGE) + 1, flags: 0,
50 addr: (struct sockaddr *) & name, addr_len: size);
51 if (nbytes < 0)
52 {
53 perror ("sendto (client)");
54 exit (EXIT_FAILURE);
55 }
56
57 /* Wait for a reply. */
58 nbytes = recvfrom (fd: sock, buf: message, MAXMSG, flags: 0, NULL, addr_len: 0);
59 if (nbytes < 0)
60 {
61 perror ("recfrom (client)");
62 exit (EXIT_FAILURE);
63 }
64
65 /* Print a diagnostic message. */
66 fprintf (stderr, "Client: got message: %s\n", message);
67
68 /* Clean up. */
69 remove (CLIENT);
70 close (fd: sock);
71}
72

source code of glibc/manual/examples/filecli.c