.\" 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.
.\"
.\" %sccs.include.redist.man%
.\"
.\"     @(#)system.3	8.1 (Berkeley) 06/04/93
.\"
.Dd 
.Dt SYSTEM 3
.Os
.Sh NAME
.Nm system
.Nd pass a command to the shell
.Sh SYNOPSIS
.Fd #include <stdlib.h>
.Ft int
.Fn system "const char *string"
.Sh DESCRIPTION
The
.Fn system
function
hands the argument
.Fa string
to the command interpreter
.Xr sh 1 .
The calling process waits for the shell
to finish executing the command,
ignoring
.Dv SIGINT
and
.Dv SIGQUIT ,
and blocking
.Dv SIGCHLD .
.Pp
If
.Fa string
is a
.Dv NULL
pointer,
.Fn system
will return non-zero if the command interpreter
.Xr sh 1
is available, and zero if it is not.
.Pp
The
.Fn system
function
returns the exit status of the shell, or \-1 if the
.Xr wait 3
for the shell failed.
A return value of 127 means the execution of the shell
failed.
.Sh SEE ALSO
.Xr sh 1 ,
.Xr execve 2 ,
.Xr wait 2 ,
.Xr popen 3
.Sh STANDARDS
The
.Fn system
function
conforms to
.St -ansiC .