Run Another Program in Linux from a C++ Program

Question

Okay so my question is this. Say I have a simple C++ code:

#include <iostream>
using namespace std;

int main(){
   cout << "Hello World" << endl;
   return 0;
}

Now say I have this program that I would like to run in my program, call it prog. Running this in the terminal could be done by:

./prog

Is there a way to just do this from my simple C++ program? For instance

#include <iostream>
using namespace std;

int main(){
   ./prog ??
   cout << "Hello World" << endl;
   return 0;
}

Any feedback would be very much obliged.

possible duplicate of http://stackoverflow.com/questions/478898/how-to-execute-a-command-and-get-output-of-command-within-c — hopia, Feb 02 '12 at 21:57
@hopia, not a duplicate. What you pointed to is a question about advanced uses of `system()`; this poster just needed to know about the function’s existence. — J. C. Salomon, Feb 02 '12 at 22:04

J. C. Salomon · Accepted Answer · 2015-03-31T00:59:45.840

24

You want the system() library call; see system(3). For example:

#include <cstdlib>

int main() {
   std::system("./prog");
   return 0;
}

The exact command string will be system-dependent, of course.

edited Mar 31 '15 at 00:59

answered Feb 02 '12 at 22:01

J. C. Salomon

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How can I get the pid of the new proc? – Gil404 May 03 '18 at 06:56
1

@Gil404: PID is a Unix concept and not all OSes have it. If you need that, use the POSIX `fork` and `exec`, or your operating system’s equivalent. – J. C. Salomon May 03 '18 at 10:47

score 9 · Answer 2 · answered Feb 09 '12 at 10:33

You can also use popen

#include <stdio.h>

int main(void)
{
        FILE *handle = popen("./prog", "r");

        if (handle == NULL) {
                return 1;
        }

        char buf[64];
        size_t readn;
        while ((readn = fread(buf, 1, sizeof(buf), handle)) > 0) {
                fwrite(buf, 1, readn, stdout);
        }

        pclose(handle);

        return 0;
}

elimirks · Answer 3 · 2014-04-21T20:09:15.203

5

You could us the system command:

system("./prog");

edited Apr 21 '14 at 20:09

answered Feb 02 '12 at 21:57

elimirks

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score 4 · Answer 4 · answered Feb 02 '12 at 21:57

4

Try system(3) :

system("./prog");

answered Feb 02 '12 at 21:57

James M

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In . And maybe slap an std:: on that system. – Captain Giraffe Feb 02 '12 at 21:59

score 2 · Answer 5 · answered Feb 02 '12 at 21:58

You could use a system call like this: http://www.cplusplus.com/reference/clibrary/cstdlib/system/

Careful if you use user input as a parameter, its a good way to have some unintended consequences. Scrub everything!

Generally, system calls can be construed as bad form.

Run Another Program in Linux from a C++ Program

5 Answers5

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