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



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 chil-
     dren 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 P_PID, waitid waits for the child with a
          process ID equal to (pid_t) id.

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

          If idtype is P_ALL, 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 sig-
                    nal.

     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 siginfo_t structure, as defined in
     siginfo(5).  siginfo_t is filled in by the system with the
     status of the process being waited for.



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



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

     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 calling process has no existing
                    unwaited-for child processes, or the set of
                    processes specified by the arguments idtype
                    and id can never be in the states specified
                    by the argument options.

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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