#include <stdio.h>
#include <stdlib.h>  /* atoi */
#include <unistd.h>  /* getpid */

#include <sys/types.h>  

#include <signal.h>
#include <sys/wait.h>

#include <errno.h>  

void do_wait(int signal);

int main(int argc, char *argv[])
{
	int						pid;

	if ( SIG_ERR == sigset(SIGCHLD, do_wait))
		perror("signal");

	switch(	pid = fork())
	{
		case -1:
			perror("fork");
			break;

		case 0:
			
			sleep(5);
			fprintf(stderr,"MSG: \"%d\"\n",getpid());
			fflush(stderr);
			sleep(5);

			exit(0);			
			break;
		
		default:
			fprintf(stderr, "spawned %d\n", pid );
			fflush(stderr);
			break;
	}


	sigpause(SIGCLD);
	sighold(SIGCLD);

	exit(errno);
}

/************************************************************************/

void do_wait(int sig)
{
int st;
int wpid;


wpid = wait ( &st );

fprintf(stderr, "wait: died %d\n", wpid);
if (WIFSTOPPED(st))
{
	fprintf(stderr,"stoped %d\n", WSTOPSIG(st));
}
else if(WIFEXITED(st))
{
	fprintf(stderr, "do_wait: %d exit with %d\n", wpid, WEXITSTATUS(st));
}
else if(WIFSIGNALED(st))
{
	fprintf(stderr,"signaled %d\n", WTERMSIG(st));
}
if(st&0200)
	fprintf(stderr, "core dumped\n");


fprintf(stderr, "do_wait: died %d\n", wpid);
fflush(stderr);
sigset(SIGCHLD, do_wait);
}