WAIT(S)                  XENIX System V                   WAIT(S)



     Name
          wait - Waits for a child process to stop or terminate.

     Syntax
          int wait (stat_loc)
          int *stat_loc;

          int wait ((int *)0)

     Description
          wait suspends the calling process until it receives a signal
          that is to be caught (see signal(S)), or until any one of
          the calling process' child processes stops in a trace mode
          (see ptrace(S)) or terminates.  If a child process stopped
          or terminated prior to the call on wait, return is
          immediate.

          If stat_loc (taken as an integer) is nonzero, 16 bits of
          information called ``status'' are stored in the low-order 16
          bits of the location pointed to by stat_loc.  Status can be
          used to differentiate between stopped and terminated child
          processes and if the child process terminated, status
          identifies the cause of termination and passes useful
          information to the parent. This is accomplished in the
          following manner:

               If the child process stopped, the high-order 8 bits of
               status will be zero and the low-order 8 bits will be
               set equal to 0177.

               If the child process terminated due to an exit call,
               the low-order 8 bits of status will be zero 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(S).

               If the child process terminated due to a signal, the
               high-order 8 bits of status will be zero and the low-
               order 8 bits will contain the number of the signal that
               caused the termination. In addition, if the low-order
               seventh bit (i.e., bit 200) is set, a ``core image''
               will have been produced; see signal(S).

          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(S).








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     WAIT(S)                  XENIX System V                   WAIT(S)



          wait will fail and return immediately if one or more of the
          following are true:

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

               stat_loc points to an illegal address.  [EFAULT]

     Return Value
          If wait returns due to the receipt of a signal, a value of
          -1 is returned to the calling process and errno is set to
          EINTR.  If wait returns due to a stopped or terminated child
          process, 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.

     See Also
          exec(S), exit(S), fork(S), pause(S), signal(S)

     Warning
          See Warning in signal(S).


































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