waitid(2)                         SDK R4.11                        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);

   where:
       idtype PPID, PGID, or PALL
       id     A process identifier
       infop  A structure to contain information
       options
              0 or a positive integer (see "Option Flags" below)

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.

   Option Flags
       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) or dg_xtrace(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.

ACCESS CONTROL
       No access checking is performed.

RETURN VALUE
       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.

DIAGNOSTICS
       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.

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


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