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orphan_process.c
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orphan_process.c
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#include "apue.h"
#include <errno.h>
static void sig_hup(int signo)
{
printf("SIGHUP received, pid = %ld\n", (long)getpid());
}
static void sig_ttin(int signo)
{
printf("SIGTTIN received, pid = %ld\n", (long)getpid());
}
static void pr_ids(char *name)
{
printf("%s: pid = %ld, ppid = %ld, pgrp = %ld, tpgrp = %ld\n", name, (long)getpid(), (long)getppid(), (long)getpgrp(), (long)tcgetpgrp(STDIN_FILENO));
fflush(stdout);
}
int main(void)
{
char c;
pid_t pid;
pr_ids("parent");
if ((pid = fork()) < 0) {
err_sys("fork error");
} else if (pid > 0) { /* parent */
sleep(1); /* sleep to let child stop itself */
} else { /* child */
pr_ids("child");
signal(SIGHUP, sig_hup); /* establish signal handler */
signal(SIGTTIN, sig_ttin);
kill(getpid(), SIGTSTP); /* stop ourself */
//kill(getpid(), SIGTTIN);
pr_ids("child"); /* prints only if we're continued */
if (read(STDIN_FILENO, &c, 1) != 1)
printf("read error %d on controlling TTY\n", errno);
}
exit(0);
}