std:: system

Calls the host environment's command processor (e.g. /bin/sh , cmd.exe ) 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 the host environment has a command processor and returns a nonzero value if and only if the command processor exists.

Parameters

Return value

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

Notes

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

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

An explicit flush of std::cout is also necessary before a call to std::system , if the spawned process performs any screen I/O.

Example

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

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