system, _wsystem

Executes a command.

Wichteg

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

C

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.

C

// crt_system.c

#include <process.h>

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

Input: crt_system.txt

Input

Line one.
Line two.

Output

Output

Line one.
Line two.

See also

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