WAIT(2-SVR4)        RISC/os Reference Manual         WAIT(2-SVR4)



NAME
     wait - wait for child process to stop or terminate

SYNOPSIS
     #include <sys/types.h>
     #include <sys/wait.h>

     pidt wait(int *statloc);

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 sig-
          nal(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(5).

     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).




                        Printed 11/19/92                   Page 1

WAIT(2-SVR4)        RISC/os Reference Manual         WAIT(2-SVR4)



     wait will fail if one or both of the following is true:

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

     EINTR          The function was interrupted by a signal.

SEE ALSO
     exec(2), exit(2), fork(2), intro(2), pause(2), ptrace(2),
     signal(2), signal(5), wstat(5).

NOTES
     See NOTES in signal(2).

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

DIAGNOSTICS
     If wait returns due to a stopped or terminated child pro-
     cess, the process ID of the child is returned to the calling
     process.  Otherwise, a value of -1 is returned and errno is
     set to indicate the error.

































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