gistfile1.h

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <sys/socket.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>

/* listening socket descriptor. */
int _server_sock;

/* Holds descriptors to be read. */
int _read_descrs[256]; 
int _read_descrcount = 0;

int setup_socket() {
    int lsock, csockinfosize;
    struct sockaddr_in lsockaddr, csockinfo;

    /* Clear/init some data. */
    memset(&lsockaddr, 0, sizeof(lsockaddr));
    memset(&csockinfo, 0, sizeof(csockinfo));
    csockinfosize = sizeof(csockinfo);

    /* Setup our server socket to a listening state. */
    lsockaddr.sin_family = AF_INET;
    lsockaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    lsockaddr.sin_port = htons(13373);

    if((lsock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
        return -1;
    if(bind(lsock, (struct sockaddr*)&lsockaddr, sizeof(lsockaddr)) < 0)
        return -1;
    if(listen(lsock, 1) < 0)
        return -1;

    /* Set as non blocking so we can select() the mother fucker. */
    fcntl(lsock, O_NONBLOCK);

    /* Update global vars and add socket to read queue for accepts. */
    _server_sock = lsock;
    _read_descrs[0] = _server_sock;
    _read_descrcount++;    
    return 0;
}

int poll_io() {
    int i;
    fd_set read_list;
    FD_ZERO(&read_list);

    for(i = 0; i < _read_descrcount; i++)
        FD_SET(_read_descrs[i], &read_list);

    /* Do select then step thru list. */
    select(FD_SETSIZE, &read_list, NULL, NULL, NULL);

    for(i = 0; i < _read_descrcount; i++) {
        /* The server socket. */
        if(i == 0 && FD_ISSET(_read_descrs[i], &read_list)) {
            int tmp = accept(_server_sock, NULL, 0);
            printf("hi %d\n", i);
            close(tmp);
        }
        else if(FD_ISSET(_read_descrs[i], &read_list)) {
            printf("a client is ready %d\n", i);
        }
    }
    return 0;
}