Regarding QProcess-Readstdout

[stampede]

Probably messages are buffered, so you wont get them until the buffer is flushed.
If this external program is made by you, you can force flushing by

std::cout << "a message" << std::flush; // C++
fflush(stdout); // C/C++

std::cout << "a message" << std::flush; // C++
fflush(stdout); // C/C++

To copy to clipboard, switch view to plain text mode