1.\" $NetBSD: system.3,v 1.7 1996/02/16 22:30:46 jtc Exp $ 2.\" 3.\" Copyright (c) 1990, 1991 The Regents of the University of California. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" the American National Standards Committee X3, on Information 8.\" Processing Systems. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. All advertising materials mentioning features or use of this software 19.\" must display the following acknowledgement: 20.\" This product includes software developed by the University of 21.\" California, Berkeley and its contributors. 22.\" 4. Neither the name of the University nor the names of its contributors 23.\" may be used to endorse or promote products derived from this software 24.\" without specific prior written permission. 25.\" 26.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36.\" SUCH DAMAGE. 37.\" 38.\" from: @(#)system.3 6.5 (Berkeley) 6/29/91 39.\" 40.Dd June 29, 1991 41.Dt SYSTEM 3 42.Os 43.Sh NAME 44.Nm system 45.Nd pass a command to the shell 46.Sh SYNOPSIS 47.Fd #include <stdlib.h> 48.Ft int 49.Fn system "const char *string" 50.Sh DESCRIPTION 51The 52.Fn system 53function 54hands the argument 55.Fa string 56to the command interpreter 57.Xr sh 1 . 58The calling process waits for the shell to 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. 73Otherwise, 74.Fn system 75returns the termination status of the shell in the format specified by 76.Xr waitpid 2 . 77.Sh RETURN VALUES 78If a child process cannot be created, or the termination status of 79the shell cannot be obtained, 80.Fn system 81returns -1 and sets 82.Va errno 83to indicate the error. 84If execution of the shell fails, 85.Fn system 86returns the termination status for a program that terminates with a call of 87.Fn exit 127 . 88.Sh SEE ALSO 89.Xr sh 1 , 90.Xr execve 2 , 91.Xr waitpid 2 , 92.Xr popen 3 93.Sh STANDARDS 94The 95.Fn system 96function 97conforms to 98.St -ansiC 99and 100.St -1003.2-92 . 101