16.5.3 Example of Local-Namespace Sockets

Here is an example showing how to create and name a socket in the local namespace.

     #include <stddef.h>
     #include <stdio.h>
     #include <errno.h>
     #include <stdlib.h>
     #include <string.h>
     #include <sys/socket.h>
     #include <sys/un.h>
     
     int
     make_named_socket (const char *filename)
     {
       struct sockaddr_un name;
       int sock;
       size_t size;
     
       /* Create the socket. */
       sock = socket (PF_LOCAL, SOCK_DGRAM, 0);
       if (sock < 0)
         {
           perror ("socket");
           exit (EXIT_FAILURE);
         }
     
       /* Bind a name to the socket. */
       name.sun_family = AF_LOCAL;
       strncpy (name.sun_path, filename, sizeof (name.sun_path));
       name.sun_path[sizeof (name.sun_path) - 1] = '\0';
     
       /* The size of the address is
          the offset of the start of the filename,
          plus its length,
          plus one for the terminating null byte.
          Alternatively you can just do:
          size = SUN_LEN (&name);
      */
       size = (offsetof (struct sockaddr_un, sun_path)
               + strlen (name.sun_path) + 1);
     
       if (bind (sock, (struct sockaddr *) &name, size) < 0)
         {
           perror ("bind");
           exit (EXIT_FAILURE);
         }
     
       return sock;
     }