bind_listen.c

#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#define MY_SOCK_PATH "/somepath"
#define LISTEN_BACKLOG 50

#define handle_error(msg) \
    do { perror(msg); exit(EXIT_FAILURE); } while (0)

int
main(int argc, char *argv[])
{
    int sfd, cfd;
    struct sockaddr_in my_addr, peer_addr;
    socklen_t peer_addr_size;

    sfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sfd == -1)
        handle_error("socket");

    memset(&my_addr, 0, sizeof(struct sockaddr_in));
                        /* Clear structure */
    my_addr.sin_family = AF_INET;
    my_addr.sin_port = htons(23456);
    my_addr.sin_addr.s_addr = htonl(INADDR_ANY);

    if (bind(sfd, (struct sockaddr *) &my_addr,
            sizeof(struct sockaddr_in)) == -1)
        handle_error("bind");

    printf("socket bound, press ENTER");
    getchar();

    if (listen(sfd, LISTEN_BACKLOG) == -1)
        handle_error("listen");

    printf("socket listening, press ENTER");
    getchar();

    /* Now we can accept incoming connections one
       at a time using accept(2) */

    peer_addr_size = sizeof(struct sockaddr_in);
    cfd = accept(sfd, (struct sockaddr *) &peer_addr,
                 &peer_addr_size);
    if (cfd == -1)
        handle_error("accept");

    /* Code to deal with incoming connection(s)... */

    /* When no longer required, the socket pathname, MY_SOCK_PATH
       should be deleted using unlink(2) or remove(3) */
}