child.c

APUE(第二版)的随书源代码,与第一版的代码相比增加了一些章节的代码(详见第二版的说明)

#include	<sys/types.h>
#include	<signal.h>
#include	<stdio.h>

static void	sig_cld();

int
main()
{
	pid_t	pid;

	if (signal(SIGCLD, sig_cld) == -1)
		perror("signal error");

	if ( (pid = fork()) < 0)
		perror("fork error");
	else if (pid == 0) {		/* child */
		sleep(2);
		_exit(0);
	}
	pause();	/* parent */
	exit(0);
}

static void
sig_cld()
{
	pid_t	pid;
	int		status;

	printf("SIGCLD received\n");
	if (signal(SIGCLD, sig_cld) == -1)	/* reestablish handler */
		perror("signal error");

	if ( (pid = wait(&status)) < 0)		/* fetch child status */
		perror("wait error");
	printf("pid = %d\n", pid);
	return;		/* interrupts pause() */
}