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c++multithreadingshellsystemstd

How to run iostream system command in the same thread?

I'm trying to execute a command using std::system from Unreal Engine C++

FString command = FString("start /B cmd /k python \"D:/app.py\"");
std::string comm(TCHAR_TO_UTF8(*command));
std::system(comm.c_str());

The command itself is working as expected, however, I need it to execute on the current thread, or alternatively check if it's finished before continuing because the next operations depend on the completion of this command

Is there a way to do it? or maybe I should use another command?

Thanks, Eden

Solution

  • The std::system function will not return until the command you execute have finished running.

    Also on Windows (which you seem to be running) then system will invoke the command interpreter (cmd) for execution of the command, which means the command you want to execute must be in the command interpreters PATH (or be an internal command of the command interpreter).

    If python is in the PATH, then you could run the python command directly, without using start or cmd (especially since then you would have two instances of cmd running), and the system function would block and not return until the python command finished running:

    FString command = FString("python \"D:/VRoscopy_repo/VRoscopy/conversion/invesalius3-master/app.py\" --no-gui -i \"D:\VRoscopy_repo\DICOM\Human\MedDream\Body\" -t 200,3033 -e \"D:\VRoscopy_repo\DICOM\Human\MedDream\Body/VRoscopy27777BED4B650CE6AFE884B365C56BCC.stl\"");