Avoiding zombie processes

messaged.c

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <signal.h>

#define PIPENAME "foopipe"
#define MAXLEN 100

int main(int argc, char *argv[])
{
	char buf[MAXLEN];
	FILE *f;
	int pid;
	/* with sigaction: 
	struct sigaction act;
	act.sa_handler = SIG_IGN;
	act.sa_flags = SA_NOCLDSTOP;
	sigaction(SIGCHLD, &act, NULL); */
	f = fopen(PIPENAME, "r");
	/* with sigignore: */
	sigignore(SIGCHLD);
	while (1) {
		fgets(buf, MAXLEN - 1, f);
		pid = fork();
		if (pid == 0)
			execlp("xmessage", "xmessage", buf, NULL);
		if (feof(f) == 0) {
			fclose(f);
			f = fopen(PIPENAME, "r");
		}
	}
	return 0;
}