Sun Microsystems, Inc. gratefully acknowledges The Open Group for
permission to reproduce portions of its copyrighted documentation.
Original documentation from The Open Group can be obtained online at
http://www.opengroup.org/bookstore/.
The Institute of Electrical and Electronics Engineers and The Open
Group, have given us permission to reprint portions of their
documentation.
In the following statement, the phrase ``this text'' refers to portions
of the system documentation.
Portions of this text are reprinted and reproduced in electronic form
in the SunOS Reference Manual, from IEEE Std 1003.1, 2004 Edition,
Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6,
Copyright (C) 2001-2004 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy
between these versions and the original IEEE and The Open Group
Standard, the original IEEE and The Open Group Standard is the referee
document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html.
This notice shall appear on any product containing this material.
The contents of this file are subject to the terms of the
Common Development and Distribution License (the "License").
You may not use this file except in compliance with the License.
You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
or http://www.opensolaris.org/os/licensing.
See the License for the specific language governing permissions
and limitations under the License.
When distributing Covered Code, include this CDDL HEADER in each
file and include the License file at usr/src/OPENSOLARIS.LICENSE.
If applicable, add the following below this CDDL HEADER, with the
fields enclosed by brackets "[]" replaced with your own identifying
information: Portions Copyright [yyyy] [name of copyright owner]
Copyright 1989 AT&T
Portions Copyright (c) 1992, X/Open Company Limited. All Rights Reserved.
Copyright (c) 2004, Sun Microsystems, Inc. All Rights Reserved.
#include <wait.h> int waitid(idtype_t idtype, id_t id, siginfo_t *infop, int options);
The waitid() function suspends the calling process until one of its child processes changes state. It records the current state of a child in the structure pointed to by infop. It returns immediately if a child process changed state prior to the call.
The idtype and id arguments specify which children waitid() is to wait for, as follows:
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 child and id is ignored.
The options argument is used to specify which state changes waitid() is to wait for. It is formed by bitwise OR operation of any of the following flags: WCONTINUED
Return the status for any child that was stopped and has been continued.
Wait for process(es) to exit.
Return immediately.
Keep the process in a waitable state.
Wait for and return the process status of any child that has stopped upon receipt of a signal.
Wait for traced process(es) to become trapped or reach a breakpoint (see ptrace(3C)).
The infop argument must point to a siginfo_t structure, as defined in siginfo.h(3HEAD). If waitid() returns because a child process was found that satisfies the conditions indicated by the arguments idtype and options, then the structure pointed to by infop will be filled by the system with the status of the process. The si_signo member will always be equal to SIGCHLD.
One instance of a SIGCHLD signal is queued for each child process whose status has changed. If waitid() returns because the status of a child process is available and WNOWAIT was not specified in options, any pending SIGCHLD signal associated with the process ID of that child process is discarded. Any other pending SIGCHLD signals remain pending.
If waitid() returns due to a change of state of one of its children and WNOHANG was not used, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error. If WNOHANG was used, 0 can be returned (indicating no error); however, no children may have changed state if infop->si_pid is 0.
The waitid() function will fail if: ECHILD
The set of processes specified by idtype and id does not contain any unwaited processes.
The infop argument points to an illegal address.
The waitid() function was interrupted due to the receipt of a signal by the calling process.
An invalid value was specified for options, or idtype and id specify an invalid set of processes.
With options equal to WEXITED | WTRAPPED, waitid() is equivalent to waitpid(3C). With idtype equal to P_ALL and options equal to WEXITED | WTRAPPED, waitid() is equivalent to wait(3C).
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE ATTRIBUTE VALUE |
| Interface Stability Standard |
| MT-Level Async-Signal-Safe |
Intro(2), exec(2), exit(2), fork(2), pause(2), sigaction(2), ptrace(3C), signal(3C), siginfo.h(3HEAD), wait(3C), waitpid(3C), attributes(5), standards(5)