Copyright (c) 2006, Sun Microsystems, Inc. All Rights Reserved.
Copyright 1989 AT&T
Portions Copyright (c) 1992, X/Open Company Limited. All Rights Reserved.
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 Sun OS 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]
#include <stdlib.h> int system(const char *string);
The system() function causes string to be given to the shell as input, as if string had been typed as a command at a terminal. The invoker waits until the shell has completed, then returns the exit status of the shell in the format specified by waitpid(3C).
If string is a null pointer, system() checks if the shell exists and is executable. If the shell is available, system() returns a non-zero value; otherwise, it returns 0.
The system() function sets the SIGINT and SIGQUIT signals to be ignored, and blocks the SIGCHLD signal for the calling thread, while waiting for the command to terminate. The system() function does not affect the termination status of any child of the calling processes other than the process it creates.
The termination status of the process created by the system() function is not affected by the actions of other threads in the calling process (it is invisible to wait(3C)) or by the disposition of the SIGCHLD signal in the calling process, even if it is set to be ignored. No SIGCHLD signal is sent to the process containing the calling thread when the command terminates.
The system() function executes posix_spawn(3C) to create a child process running the shell that in turn executes the commands in string. If posix_spawn() fails, system() returns -1 and sets errno to indicate the error; otherwise the exit status of the shell is returned.
The system() function may set errno values as described by fork(2), in particular:
EAGAIN
A resource control or limit on the total number of processes, tasks or LWPs under execution by a single user, task, project, or zone has been exceeded, or the total amount of system memory available is temporarily insufficient to duplicate this process.
ENOMEM
There is not enough swap space.
EPERM
The {PRIV_PROC_FORK} privilege is not asserted in the effective set of the calling process.
The system() function manipulates the signal handlers for SIGINT and SIGQUIT. It is therefore not safe to call system() in a multithreaded process, since some other thread that manipulates these signal handlers and a thread that concurrently calls system() can interfere with each other in a destructive manner. If, however, no such other thread is active, system() can safely be called concurrently from multiple threads. See popen(3C) for an alternative to system() that is thread-safe.
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| Interface Stability | Standard |
| MT-Level | Unsafe |
ksh(1), sh(1), popen(3C), posix_spawn(3C), wait(3C), waitpid(3C), attributes(5), standards(5)