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. All advertising materials mentioning features or use of this software 17.\" must display the following acknowledgement: 18.\" This product includes software developed by the University of 19.\" California, Berkeley and its contributors. 20.\" 4. Neither the name of the University nor the names of its contributors 21.\" may be used to endorse or promote products derived from this software 22.\" without specific prior written permission. 23.\" 24.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34.\" SUCH DAMAGE. 35.\" 36.\" @(#)system.3 8.1 (Berkeley) 6/4/93 37.\" $Id$ 38.\" 39.Dd June 4, 1993 40.Dt SYSTEM 3 41.Os 42.Sh NAME 43.Nm system 44.Nd pass a command to the shell 45.Sh SYNOPSIS 46.Fd #include <stdlib.h> 47.Ft int 48.Fn system "const char *string" 49.Sh DESCRIPTION 50The 51.Fn system 52function 53hands the argument 54.Fa string 55to the command interpreter 56.Xr sh 1 . 57The calling process waits for the shell 58to finish executing the command, 59ignoring 60.Dv SIGINT 61and 62.Dv SIGQUIT , 63and blocking 64.Dv SIGCHLD . 65.Pp 66If 67.Fa string 68is a 69.Dv NULL 70pointer, 71.Fn system 72will return non-zero if the command interpreter 73.Xr sh 1 74is available, and zero if it is not. 75.Pp 76The 77.Fn system 78function 79returns the exit status of the shell as returned by 80.Xr waitpid 2 , 81or \-1 if an error occurred when invoking 82.Xr fork 2 83or 84.Xr waitpid 2 . 85A return value of 127 means the execution of the shell 86failed. 87.Sh SEE ALSO 88.Xr sh 1 , 89.Xr execve 2 , 90.Xr fork 2 , 91.Xr waitpid 2 , 92.Xr popen 3 93.Sh STANDARDS 94The 95.Fn system 96function 97conforms to 98.St -ansiC . 99and is expected to be 100.St -p1003.2 101compatible. 102