wait(3)                     Library Functions Manual                     wait(3)

       wait - check child process status

       #include <wait.h>

       int wait_nohang(&wstat);
       int wait_stop(&wstat);
       int wait_stopnohang(&wstat);
       int wait_pid(&wstat,pid);

       int wait_exitcode(wstat);
       int wait_crashed(wstat);
       int wait_stopped(wstat);
       int wait_stopsig(wstat);

       int pid;
       int wstat;

       wait_nohang looks for zombies (child processes that have exited).  If it
       sees a zombie, it eliminates the zombie, puts the zombie's exit status
       into wstat, and returns the zombie's process ID.  If there are several
       zombies, wait_nohang picks one.  If there are children but no zombies,
       wait_nohang returns 0.  If there are no children, wait_nohang returns -1,
       setting errno appropriately.

       wait_stopnohang is similar to wait_nohang, but it also looks for children
       that have stopped.

       wait_stop is similar to wait_stopnohang, but if there are children it
       will pause waiting for one of them to stop or exit.

       wait_pid waits for child process pid to exit.  It eliminates any zombie
       that shows up in the meantime, discarding the exit status.

       wait_stop and wait_pid retry upon error_intr.

       If the child stopped, wait_stopped is nonzero; wait_stopsig is the signal
       that caused the child to stop.

       If the child exited by crashing, wait_stopped is zero; wait_crashed is

       If the child exited normally, wait_stopped is zero; wait_crashed is zero;
       and wait_exitcode is the child's exit code.

       wait(2), error(3)