wait(2)                                                      wait(2)


       NAME
             wait - wait for child process to stop or terminate

       SYNOPSIS
             #include <sys/types.h>
             #include <sys/wait.h>
             pid_t wait(int *stat_loc);

       DESCRIPTION
             wait suspends the calling process until one of its immediate
             children terminates or until a child that is being traced
             stops because it has received a signal.  The wait system call
             will return prematurely if a signal is received.  If all child
             processes stopped or terminated prior to the call on wait,
             return is immediate.

             If wait returns because the status of a child process is
             available, it returns the process ID of the child process.  If
             the calling process had specified a non-zero value for
             stat_loc, the status of the child process will be stored in
             the location pointed to by stat_loc.  It may be evaluated with
             the macros described on wstat(5).  In the following, status is
             the object pointed to by stat_loc:

                   If the child process stopped, the high order 8 bits of
                   status will contain the number of the signal that caused
                   the process to stop and the low order 8 bits will be set
                   equal to WSTOPFLG.

                   If the child process terminated due to an exit call, the
                   low order 8 bits of status will be 0 and the high order
                   8 bits will contain the low order 8 bits of the argument
                   that the child process passed to exit.  [see exit(2)].

                   If the child process terminated due to a signal, the
                   high order 8 bits of status will be 0 and the low order
                   8 bits will contain the number of the signal that caused
                   the termination. In addition, if WCOREFLG is set, a
                   ``core image'' will have been produced. [see signal(2)].

             If wait returns because the status of a child process is
             available, then that status may be evaluated with the macros
             defined by wstat.





                           Copyright 1994 Novell, Inc.               Page 1

      wait(2)                                                      wait(2)


            If a parent process terminates without waiting for its child
            processes to terminate, the parent process ID of each child
            process is set to 1.  This means the initialization process
            inherits the child processes. [see intro(2)].

         Files
            Message catalog:  uxcore.abi

         Return Values
            If wait returns due to a stopped or terminated child process,
            the process ID of the child is returned to the calling
            process.  Otherwise, wait returns -1 and sets errno to
            identify the error.

         Errors
            In the following conditions, wait fails and sets errno to:

            ECHILD         The calling process has no existing unwaited-
                           for child processes.

            EINTR          The function was interrupted by a signal.

      REFERENCES
            exec(2), exit(2), fork(2), intro(2), pause(2), ptrace(2),
            signal(2), signal(5), wstat(5)

      NOTICES
            See NOTICES in signal(5).

            If SIGCLD is held, then wait does not recognize death of
            children.

         Considerations for Threads Programming
            While one thread is blocked, siblings might still be
            executing.













                          Copyright 1994 Novell, Inc.               Page 2