NAME
          wait - check child process status

     SYNTAX
          #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;

     DESCRIPTION
          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.

     STATUS PARSING
          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 nonzero.

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

     SEE ALSO
          wait(2), error(3)