Question

Ok suppose I have a program ( in windows a .exe file ) and when I run it, it outputs some information… now I’m writing another program ( in c++ ) and I need it to automatically run that .exe file and read the output so that it can process that information for further actions…

what should I do ?

Answer 1

Use popen or on windows (per comment) _popen. Basically it functions as the thing behind the | in some program | thing.

Normally I’m against posting complete code but I literally wrote this today and have it on hand, so, here you go. From what I understand C++ doesn’t have a great interface that replaces popen but if you’re bringing in the boost libraries or something at that layer there are solutions.

Note I use char[10] because in my application I know the output will be that short.

   PopenWrapper(const std::string& command) {

            fd = popen(command.c_str(), "r");
            if(fd == NULL) {
                    throw PopenException("Failed to open command: " + command);
            }
    }

    std::string get() {
            char line[10];
            fgets(line, sizeof(line), fd);
            return std::string(line);
    }

    ~PopenWrapper() {
            if(fd != NULL) {
                    pclose(fd);
            }
    }