.\" Copyright (c) 1990, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the American National Standards Committee X3, on Information
.\" Processing Systems.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)system.3	8.1 (Berkeley) 6/4/93
.\"
.\" $FreeBSD$
.Dd June 4, 1993
.Dt SYSTEM 3
.Os
.Sh 名称
.Nm system
.Nd コマンドをシェルに渡す
.Sh 書式
.Fd #include <stdlib.h>
.Ft int
.Fn system "const char *string"
.Sh 解説
.Fn system
関数は、引数
.Fa string
をコマンドインタープリタ
.Xr sh 1
に
渡します。呼び出し側プロセスは、シェルがそのコマンドの実行を完了するまで
待ち、
.Dv SIGINT
および
.Dv SIGQUIT
を無視し、
.Dv SIGCHLD
をブロックします。
.Pp
.Fa string
が
.Dv NULL
ポインタである場合は、
.Fn system
はコマンドインタープリタ
.Xr sh 1
が利用できる場合は非ゼロの値を返し、利用できない場合はゼロを
返します。
.Pp
.Fn system
関数は、シェルの終了ステータス、またはシェルについての
.Xr wait 2
が失敗した場合は
\-1 を返します。戻り値
127 は、シェルの実行が
失敗したことを意味します。
.Sh 参照
.Xr sh 1 ,
.Xr execve 2 ,
.Xr wait 2 ,
.Xr popen 3
.Pp
.Sh 規格
.Fn system
関数は、
.St -ansiC
に準拠しており、
.St -p1003.2
と互換性があると考えられます。