signal in C

wire_signal.c

#include <signal.h>
#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <bits/signum.h>

int val=0;
int pipefd[2];
#define RPIPE 0
#define WPIPE 1
void send_sig(int signal) { 
   write(pipefd[WPIPE], &signal, 1);
}

int main(void) {
   int signal_received=0;
   printf("hello word\n");

    pipe(pipefd);
    fcntl(pipefd[RPIPE],F_SETFD, O_NONBLOCK);
    fcntl(pipefd[WPIPE],F_SETFD, O_NONBLOCK);

    signal(SIGHUP,send_sig);
    signal(SIGUSR1,send_sig);

    for(;;) { 
       printf("%s","processing\0");
       char buf[1];
       while(read(pipefd[RPIPE],buf,1) !=0 || errno != EINTR){
        printf("received sig; (%d)%d\n",signal_received++, (int )*buf);
        printf("E:%d\n", errno);
     }
        pause();
    }
}