/* af_inet.c: *  * Establishing a Specific AF_INET * Socket Address: */#include <stdio.h>#include <unistd.h>#include <stdlib.h>#include <errno.h>#include <string.h>#include <sys/types.h>#include <sys/stat.h>#include <sys/socket.h>#include <netinet/in.h>/* * This function reports the error and * exits back to the shell : */static voidbail(const char *on_what) {    perror(on_what);    exit(1);}intmain(int argc,char **argv,char **envp) {    int z;           /* Status return code */    int sck_inet;               /* Socket  */    struct sockaddr_in adr_inet;/* AF_INET */    int len_inet;               /* length  */    const unsigned char IPno[] = {        127, 0, 0, 23    /* Local loopback */    };    /* Create an IPv4 Internet Socket */    sck_inet = socket(AF_INET,SOCK_STREAM,0);    if ( sck_inet == -1 )        bail("socket()");    /* Create an AF_INET address */    memset(&adr_inet,0,sizeof adr_inet);    adr_inet.sin_family = AF_INET;    adr_inet.sin_port = htons(9000);    memcpy(&adr_inet.sin_addr.s_addr,IPno,4);    len_inet = sizeof adr_inet;    /* Now bind the address to the socket */    z = bind(sck_inet,        (struct sockaddr *)&adr_inet,        len_inet);    if ( z == -1 )        bail("bind()");    /* Display all of our bound sockets */    system("netstat -pa --tcp 2>/dev/null | "        "sed -n '1,/^Proto/p;/af_inet/p'");    close(sck_inet);    return 0;}