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	1	.\" Copyright (c) 1990, 1991, 1993
	2	.\" The Regents of the University of California. All rights reserved.
	3	.\"
	4	.\" This code is derived from software contributed to Berkeley by
	5	.\" the American National Standards Committee X3, on Information
	6	.\" Processing Systems.
	7	.\"
	8	.\" Redistribution and use in source and binary forms, with or without
	9	.\" modification, are permitted provided that the following conditions
	10	.\" are met:
	11	.\" 1. Redistributions of source code must retain the above copyright
	12	.\" notice, this list of conditions and the following disclaimer.
	13	.\" 2. Redistributions in binary form must reproduce the above copyright
	14	.\" notice, this list of conditions and the following disclaimer in the
	15	.\" documentation and/or other materials provided with the distribution.
	16	.\" 3. Neither the name of the University nor the names of its contributors
	17	.\" may be used to endorse or promote products derived from this software
	18	.\" without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	.\" SUCH DAMAGE.
	31	.\"
	32	.\" @(#)system.3 8.1 (Berkeley) 6/4/93
	33	.\" $FreeBSD: src/lib/libc/stdlib/system.3,v 1.13 2008/06/26 08:24:59 danger Exp $
	34	.\" $DragonFly: src/lib/libc/stdlib/system.3,v 1.2 2003/06/17 04:26:46 dillon Exp $
	35	.\"
	36	.Dd June 4, 1993
	37	.Dt SYSTEM 3
	38	.Os
	39	.Sh NAME
	40	.Nm system
	41	.Nd pass a command to the shell
	42	.Sh LIBRARY
	43	.Lb libc
	44	.Sh SYNOPSIS
	45	.In stdlib.h
	46	.Ft int
	47	.Fn system "const char *string"
	48	.Sh DESCRIPTION
	49	The
	50	.Fn system
	51	function
	52	hands the argument
	53	.Fa string
	54	to the command interpreter
	55	.Xr sh 1 .
	56	The calling process waits for the shell
	57	to finish executing the command,
	58	ignoring
	59	.Dv SIGINT
	60	and
	61	.Dv SIGQUIT ,
	62	and blocking
	63	.Dv SIGCHLD .
	64	.Pp
	65	If
	66	.Fa string
	67	is a
	68	.Dv NULL
	69	pointer,
	70	.Fn system
	71	will return non-zero if the command interpreter
	72	.Xr sh 1
	73	is available, and zero if it is not.
	74	.Sh RETURN VALUES
	75	The
	76	.Fn system
	77	function
	78	returns the exit status of the shell as returned by
	79	.Xr waitpid 2 ,
	80	or \-1 if an error occurred when invoking
	81	.Xr fork 2
	82	or
	83	.Xr waitpid 2 .
	84	A return value of 127 means the execution of the shell
	85	failed.
	86	.Sh SEE ALSO
	87	.Xr sh 1 ,
	88	.Xr execve 2 ,
	89	.Xr fork 2 ,
	90	.Xr waitpid 2 ,
	91	.Xr popen 3
	92	.Sh STANDARDS
	93	The
	94	.Fn system
	95	function
	96	conforms to
	97	.St -isoC
	98	and is expected to be
	99	.St -p1003.2
	100	compatible.