Receiving with the SIGURG Signal example code

/* 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 displayError(char *on_what); extern int BindAccept(char *addr); static int s = -1; /* Socket */ /* * SIGURG signal handler: */ static void sigurg(int signo) { int n; char buf[256]; n = recv(s,buf,sizeof buf,MSG_OOB); if ( n < 0 ) { displayError("recv(2)"); } buf[n] = 0; printf("URG '%s' (%d) \n", buf,n); signal(SIGURG,sigurg); } int main(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.: */ s = BindAccept(argc >= 2 ? argv[1] : "127.0.0.1:9011"); /* * Establish ownership: */ z = fcntl(s,F_SETOWN,getpid()); if ( z == -1 ) { displayError("fcntl(2)"); } /* * Catch SIGURG: */ signal(SIGURG,sigurg); for (;;) { z = recv(s,buf,sizeof buf,0); if ( z == -1 ) { displayError("recv(2)"); } if ( z == 0 ) { break; } buf[z] = 0; printf("rcv '%s' (%d)\n", buf, z); } close(s); return 0; }