Run external .exe and receive return value from it

Question

In C++ is it possible to call/run another executable and receive a return value from that executable(for example either a 1 or 0 to signify whether the other exe performed its operations successfully)?

For simplicity, take this example, if I have an external console .exe called filelist.exe that lists all files in a directory and writes those file names to a file. If the filelist.exe runs successfully then main returns 1 and if not returns 0.

If I were to run filelist.exe using the following code, is there a way to get a return value from filelist.exe?

int res = system("filelist.exe dirPath");

// Maybe the windows function CreateProcess() allows filelist.exe to return
// a value to the currently running application?
CreateProcess();

Note I am not intending to create a simple console application that lists files in a directory I am attempting to create a console application that checks whether the user has a valid version of a 3rd party program and return 1 if they do have a valid version and 0 if not.

Answer 1

Yes, you would start another process and run the executable. What you're asking is called inter-process communication and is typically achieved through either signals or pipes in a scenario like yours.

Answer 2

An example looks as follows:

    res = CreateProcess(
        NULL,                //  pointer to name of executable module  
        commandLine,         //  pointer to command line string  
        NULL,                //  pointer to process security attributes  
        NULL,                //  pointer to thread security attributes  
        TRUE,                //  handle inheritance flag  
        0,                   //  creation flags  
        NULL,                //  pointer to new environment block  
        NULL,                //  pointer to current directory name  
        &StartupInfo,        //  pointer to STARTUPINFO  
        &ProcessInfo         //  pointer to PROCESS_INFORMATION  
      );

    if (!res)
      //  process creation failed!
      {
        showError(commandLine);
        retVal = 1;
      }
    else if (waitForCompletion)
      {
        res = WaitForSingleObject(
                ProcessInfo.hProcess,  
                INFINITE      // time-out interval in milliseconds  
                );  
        GetExitCodeProcess(ProcessInfo.hProcess, &exitCode);

        retVal = (int)exitCode;
      }

The return code of the external process is retrieved from the Process object using GetExitProcess() . This assumes that your code is waiting for completion after starting the process.