waitid(2)                                                         waitid(2)


   NAME
         waitid - wait for child process to change state

   SYNOPSIS
         #include <sys/types.h>
         #include <wait.h>
         int waitid(idtypet idtype, idt id, siginfot *infop, int options);

   DESCRIPTION
         waitid suspends the calling process until one of its children changes
         state.  It records the current state of a child in the structure
         pointed to by infop.  If a child process changed state prior to the
         call to waitid, waitid returns immediately.

         The idtype and id arguments specify which children waitid is to wait
         for.

               If idtype is PPID, waitid waits for the child with a process
               ID equal to (pidt) id.

               If idtype is PPGID, waitid waits for any child with a process
               group ID equal to (pidt)id.

               If idtype is PALL, waitid waits for any children and id is
               ignored.

         The options argument is used to specify which state changes waitid is
         to wait for.  It is formed by an OR of any of the following flags:

         WEXITED        Wait for process(es) to exit.

         WTRAPPED       Wait for traced process(es) to become trapped or reach
                        a breakpoint [see ptrace(2)].

         WSTOPPED       Wait for and return the process status of any child
                        that has stopped upon receipt of a signal.

         WCONTINUED     Return the status for any child that was stopped and
                        has been continued.

         WNOHANG        Return immediately.

         WNOWAIT        Keep the process in a waitable state.

         infop must point to a siginfot structure, as defined in siginfo(5).
         siginfot is filled in by the system with the status of the process
         being waited for.

         waitid fails if one or more of the following is true.




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   waitid(2)                                                         waitid(2)


         EFAULT         infop points to an invalid address.

         EINTR          waitid was interrupted due to the receipt of a signal
                        by the calling process.

         EINVAL         An invalid value was specified for options.

         EINVAL         idtype and id specify an invalid set of processes.

         ECHILD         The set of processes specified by idtype and id does
                        not contain any unwaited-for processes.

   DIAGNOSTICS
         If waitid returns due to a change of state of one of its children, a
         value of 0 is returned.  Otherwise, a value of -1 is returned and
         errno is set to indicate the error.

   SEE ALSO
         intro(2), exec(2), exit(2), fork(2), pause(2), ptrace(2), signal(2),
         sigaction(2), wait(2), siginfo(5).

































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