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SYSTEM(3) |
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 executing 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. Otherwise, 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 indicate the error. If execution of the shell fails, system() returns the termination status for a program that terminates with a call of exit(127).
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.
