Defined in header <cstdlib>
int system( const char* command );

Calls the host environment's command processor (/bin/sh, cmd.exe, command.com) with the parameter command. Returns an implementation-defined value (usually the value that the invoked program returns).

If command is a null pointer, checks if host environment has a command processor and returns nonzero value only if the command processor exists.


command - character string identifying the command to be run in the command processor. If a null pointer is given, command processor is checked for existence

Return value

Implementation-defined value. If command is a null pointer, returns nonzero value only if command processor exists.


On POSIX systems, the return value can be decomposed using WEXITSTATUS and WSTOPSIG.

Related POSIX function popen makes the output generated by command available to the caller.


#include <cstdlib>
#include <fstream>
#include <iostream>
int main()
    std::system("ls -l >test.txt"); // execute the UNIX command "ls -l >test.txt"
    std::cout << std::ifstream("test.txt").rdbuf();

Possible output:

total 16
-rwxr-xr-x 1 2001 2000 8859 Sep 30 20:52 a.out
-rw-rw-rw- 1 2001 2000  161 Sep 30 20:52 main.cpp
-rw-r--r-- 1 2001 2000    0 Sep 30 20:52 test.txt

See also

C documentation for system

© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.