Qt Creator - Code is running but I get an error message from the IDE

Question

As soon as I run my code (note that I'm using C only, no QT and no C++) I get the following message from the application output inside the IDE:

Cannot obtain a handle to the inferior: The parameter is incorrect.

When I delete the makefiles and debug/release folders it's running but after some time I still get the error. It's not that much of a problem though, the code runs and everything is fine but this error pops up and it's quite annoying.

The content of the .pro file is:

TEMPLATE = app
CONFIG += console
CONFIG -= app_bundle
CONFIG -= qt
QMAKE_CC = gcc -std=c99
SOURCES += main.c

Thanks in advance!

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edit: I have added C++ tag, because this error occurs also for C++ console application as in my case.

Answer 1

I have met same problem. Tips and advices on forums are rather clueless, so I investigated problem myself and I have found that it's a bug in QtCreator.

There is dirty little program called qtcreator_process_stub. Whenever you run your program within IDE, IDE first runs qtcreator_process_stub and passes your program name as parameter (among some other parameters). qtcreator_process_stub then starts your program as separate process and prints its PID (and on windows also thread id). Information is printed to the pipe and then it is read by ConsoleProcess::readStubOutput(), which is part of Utils.dll library used by QtCreator.

The problem occurs when "inferior" process (your application) finishes execution before whole communication has been processed. ConsoleProcess::readStubOutput() attempts to use OpenProcess() on non-existing process with closed handle. OpenProcess() fails hence error "Cannot obtain a handle to the inferior: The parameter is incorrect.". Whole error is not handled very gently (Uhm, and now what?)... :-/

Solution: When you add some user input action, pause, sleep, delay or just some loops, so that execution of your application is a bit longer error vanishes. There is enough time for ConsoleProcess::readStubOutput() to execute OpenProcess(), before your application quits. So as a workaroud I suggest to do that until the bug is fixed.

Answer 2

I got the same error repeatedly while working on a C++ project in Qt. I was able to solve it by copying one of the shared libraries(.dll) I was using in to the build folder.

So, if you are using any shared external libraries that are needed at runtime, make sure they are in the builds folder.