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 stackoverflow.com/questions/478898/… — hopia
– hopia, Commented Feb 2, 2012 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
– J. C. Salomon, Commented Feb 2, 2012 at 22:04

J. C. Salomon · Accepted Answer · 2015-03-31 00:59:45Z

25

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, 2015 at 0:59

answered Feb 2, 2012 at 22:01

J. C. Salomon

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2 Comments

Gil404 Over a year ago

How can I get the pid of the new proc?

J. C. Salomon Over a year ago

@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.

xda1001 · Accepted Answer · 2012-02-09 10:33:00Z

9

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;
}

answered Feb 9, 2012 at 10:33

xda1001

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Comments

elimirks · Accepted Answer · 2014-04-21 20:09:15Z

5

You could us the system command:

system("./prog");

edited Apr 21, 2014 at 20:09

answered Feb 2, 2012 at 21:57

elimirks

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Comments

James M · Accepted Answer · 2012-02-02 21:57:26Z

4

Try system(3) :

system("./prog");

answered Feb 2, 2012 at 21:57

James M

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1 Comment

Captain Giraffe Over a year ago

In <cstdlib>. And maybe slap an std:: on that system.

gmoney · Accepted Answer · 2012-02-02 21:58:16Z

2

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.

answered Feb 2, 2012 at 21:58

gmoney

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