xref: /freebsd/lib/libc/stdlib/system.3 (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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32.\"     @(#)system.3	8.1 (Berkeley) 6/4/93
33.\" $FreeBSD$
34.\"
35.Dd June 4, 1993
36.Dt SYSTEM 3
37.Os
38.Sh NAME
39.Nm system
40.Nd pass a command to the shell
41.Sh LIBRARY
42.Lb libc
43.Sh SYNOPSIS
44.In stdlib.h
45.Ft int
46.Fn system "const char *string"
47.Sh DESCRIPTION
48The
49.Fn system
50function
51hands the argument
52.Fa string
53to the command interpreter
54.Xr sh 1 .
55The calling process waits for the shell
56to finish executing the command,
57ignoring
58.Dv SIGINT
59and
60.Dv SIGQUIT ,
61and blocking
62.Dv SIGCHLD .
63.Pp
64If
65.Fa string
66is a
67.Dv NULL
68pointer,
69.Fn system
70will return non-zero if the command interpreter
71.Xr sh 1
72is available, and zero if it is not.
73.Pp
74The
75.Fn system
76function
77returns the exit status of the shell as returned by
78.Xr waitpid 2 ,
79or \-1 if an error occurred when invoking
80.Xr fork 2
81or
82.Xr waitpid 2 .
83A return value of 127 means the execution of the shell
84failed.
85.Sh SEE ALSO
86.Xr sh 1 ,
87.Xr execve 2 ,
88.Xr fork 2 ,
89.Xr waitpid 2 ,
90.Xr popen 3
91.Sh STANDARDS
92The
93.Fn system
94function
95conforms to
96.St -isoC
97and is expected to be
98.St -p1003.2
99compatible.
100