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#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <sys/signal.h>
#include <sys/wait.h>
#include <unistd.h>
void test_handler(int signo)
{
write(1, "caught SIGCHLD\n", 15);
return;
}
int main(void)
{
pid_t mypid;
struct sigaction siga;
static sigset_t sigset;
/* Set up sighandling */
sigfillset(&sigset);
siga.sa_handler = test_handler;
siga.sa_mask = sigset;
siga.sa_flags = 0;
if (sigaction(SIGCHLD, &siga, (struct sigaction *)NULL) != 0) {
fprintf(stderr, "sigaction choked: %s!", strerror(errno));
exit(EXIT_FAILURE);
}
/* Setup a child process to exercise the sig handling for us */
mypid = getpid();
if (fork() == 0) {
int i;
for (i=0; i < 3; i++) {
sleep(2);
kill(mypid, SIGCHLD);
}
_exit(EXIT_SUCCESS);
}
/* Wait for signals */
write(1, "waiting for a SIGCHLD\n",22);
for(;;) {
sleep(10);
if (waitpid(-1, NULL, WNOHANG | WUNTRACED) > 0)
break;
write(1, "after sleep\n", 12);
}
printf("Bye-bye! All done!\n");
return 0;
}
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