system, _wsystem

Executes a command.

Important

This API cannot be used in applications that execute in the Windows Runtime. For more information, see CRT functions not supported in Universal Windows Platform apps.

Syntax

int system(
   const char *command
);
int _wsystem(
   const wchar_t *command
);

Parameters

command
The command to be executed.

Return value

If command is NULL and the command interpreter is found, returns a nonzero value. If the command interpreter isn't found, returns 0 and sets errno to ENOENT. If command isn't NULL, system returns the value that is returned by the command interpreter. It returns the value 0 only if the command interpreter returns the value 0. A return value of -1 indicates an error, and errno is set to one of the following values:

Value	Description
E2BIG	The argument list (which is system-dependent) is too large.
ENOENT	The command interpreter can't be found.
ENOEXEC	The command-interpreter file can't be executed because the format isn't valid.
ENOMEM	Not enough memory is available to execute command; or available memory has been corrupted; or a non-valid block exists, which indicates that the calling process has been allocated incorrectly.

For more information about return codes, see errno, _doserrno, _sys_errlist, and _sys_nerr.

Remarks

The system function passes command to the command interpreter, which executes the string as an operating-system command. system uses the COMSPEC and PATH environment variables to locate the command-interpreter file CMD.exe. If command is NULL, the function just checks whether the command interpreter exists.

You must explicitly flush, by using fflush or _flushall, or close any stream before you call system.

_wsystem is a wide-character version of system; the command argument to _wsystem is a wide-character string. These functions behave identically otherwise.

By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.

Generic-text routine mappings

TCHAR.H routine	_UNICODE and _MBCS not defined	_MBCS defined	_UNICODE defined
_tsystem	system	system	_wsystem

Requirements

Routine	Required header
system	<process.h> or <stdlib.h>
_wsystem	<process.h> or <stdlib.h> or <wchar.h>

For more compatibility information, see Compatibility.

Example

This example uses system to TYPE a text file.

// crt_system.c

#include <process.h>

int main( void )
{
   system( "type crt_system.txt" );
}

Input: crt_system.txt

Line one.
Line two.

Output

Line one.
Line two.

See also

Process and environment control
_exec, _wexec functions
exit, _Exit, _exit
_flushall
_spawn, _wspawn functions