SYSTEM(3) BSD Library Functions Manual SYSTEM(3)
NAME
system -- pass a command to the shell
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <stdlib.h>
int
system(const char *string);
DESCRIPTION
The system() function hands the argument string to the command interpreter sh(1). The calling process waits for the shell to finish execut-
ing the command, ignoring SIGINT and SIGQUIT, and blocking SIGCHLD.
If string is a NULL pointer, system() will return non-zero, if the command interpreter is available, or zero if none is available. Other-
wise, system() returns the termination status of the shell in the format specified by waitpid(2).
RETURN VALUES
If a child process cannot be created, or the termination status of the shell cannot be obtained, system() returns -1 and sets errno to indi-
cate the error. If execution of the shell fails, system() returns the termination status for a program that terminates with a call of
exit(127).
SEE ALSO
sh(1), execve(2), waitpid(2), popen(3), shquote(3)
STANDARDS
The system() function conforms to ANSI X3.159-1989 (``ANSI C89'') and IEEE Std 1003.2-1992 (``POSIX.2'').
CAVEATS
Never supply the system() function with a command containing any part of an unsanitized user-supplied string. Shell meta-characters present
will be honored by the sh(1) command interpreter.
BSD
August 2, 2007 BSD
