/* oobrecv.c: *  * Example OOB receiver : */#include <stdio.h>#include <unistd.h>#include <stdlib.h>#include <errno.h>#include <string.h>#include <signal.h>#include <fcntl.h>#include <sys/types.h>#include <sys/socket.h>extern void bail(char *on_what);extern int BindAccept(char *addr);static int s = -1;  /* Socket *//* * SIGURG signal handler : */static voidsigurg(int signo) {    int n;    char buf[256];    n = recv(s,buf,sizeof buf,MSG_OOB);    if ( n < 0 )        bail("recv(2)");    buf[n] = 0;    printf("URG '%s' (%d)\n",        buf,n);          signal(SIGURG,sigurg);}intmain(int argc,char **argv) {    int z;            /* Status */    char buf[256];    /*     * Use a server address from the command     * line, if one has been provided.     * Otherwise, this program will default     * to using the arbitrary address     * 127.0.0.1 :     */    s = BindAccept(argc >= 2        ? argv[1]        : "127.0.0.1:9011");    /*     * Establish ownership :     */    z = fcntl(s,F_SETOWN,getpid());    if ( z == -1 )        bail("fcntl(2)");    /*     * Catch SIGURG :     */    signal(SIGURG,sigurg);    for (;;) {        z = recv(s,buf,sizeof buf,0);        if ( z == -1 )            bail("recv(2)");        if ( z == 0 )            break;        buf[z] = 0;        printf("rcv '%s' (%d)\n",            buf, z);    }    close(s);    return 0;}