std::system

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Technical Specifications

 

Utilities library

Type support (basic types, RTTI, type traits)

Dynamic memory management

Error handling

Program utilities

Variadic functions

Date and time

Function objects

initializer_list (C++11)

bitset

hash (C++11)

Relational operators

rel_ops::operator!=rel_ops::operator>rel_ops::operator<=rel_ops::operator>=

Pairs and tuples

pair

tuple (C++11)

piecewise_construct_t (C++11)

piecewise_construct (C++11)

integer_sequence (C++14)

Swap, forward and move

swap

exchange (C++14)

forward (C++11)

move (C++11)

move_if_noexcept (C++11)

Type operations

declval (C++11)

as_const (C++17)

 

Program support utilities

Program termination
abort exit quick_exit (C++11) _Exit (C++11)	atexit at_quick_exit (C++11) EXIT_SUCCESSEXIT_FAILURE
Communicating with the environment
system	getenv
Signals
signal raise sig_atomic_t	SIG_DFLSIG_IGN SIG_ERR
Signal types
SIGABRTSIGFPESIGILLSIGINTSIGSEGVSIGTERM
Non-local jumps
setjmp
longjmp
Types
jmp_buf

 

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.

Parameters

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.

Notes

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.

Example

Run this code

#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