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Defined in header <cstdlib> | ||
int system(constchar* command); | ||
Calls the host environment's command processor (e.g./bin/sh,cmd.exe) with the parametercommand. Returns an implementation-defined value (usually the value that the invoked program returns).
Ifcommand 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.
Contents |
| 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 |
Implementation-defined value. Ifcommand is a null pointer, returns a nonzero value if and only if the command processor exists.
On POSIX systems, the return value can be decomposed usingWEXITSTATUS andWSTOPSIG.
The related POSIX functionpopen makes the output generated bycommand available to the caller.
An explicit flush ofstd::cout is also necessary before a call tostd::system, if the spawned process performs any screen I/O.
#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();}
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
C documentation forsystem |
