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system, _wsystem

Executes a command.

Important note Important

This API cannot be used in applications that execute in the Windows Runtime. For more information, see CRT functions not supported with /ZW.

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


The command to be executed.

If command is NULL and the command interpreter is found, returns a nonzero value. If the command interpreter is not found, returns 0 and sets errno to ENOENT. If command is not 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:


The argument list (which is system-dependent) is too big.


The command interpreter cannot be found.


The command-interpreter file cannot be executed because the format is not valid.


Not enough memory is available to execute command; or available memory has been corrupted; or a non-valid block exists, which indicates that the process that's making the call was not allocated correctly.

See _doserrno, errno, _sys_errlist, and _sys_nerr for more information about these return codes.

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.

Generic-Text Routine Mappings

TCHAR.H routine

_UNICODE & _MBCS not defined

_MBCS defined

_UNICODE defined






Required header


<process.h> or <stdlib.h>


<process.h> or <stdlib.h> or <wchar.h>

For additional compatibility information, see Compatibility.

This example uses system to TYPE a text file.

// crt_system.c

#include <process.h>

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

Line one.
Line two.

Line one.
Line two.