Trouble configuring qt - can't find function _popen

[vega]

Hello,

I'm trying to build stellarium from source but I've run into a problem configuring qt. When I try and run the configure.bat script, I get the following errors:

C:/qt5/qtbase/qmake/library/qmakebuiltins.cpp: In member function 'QByteArray QMakeEvaluator::getCommandOutput(const QString&, int*) const':
C:/qt5/qtbase/qmake/library/qmakebuiltins.cpp:76:18: error: '_popen' was not declared in this scope; did you mean '_lopen'?
   76 | #define QT_POPEN _popen
      |                  ^~~~~~

C:/qt5/qtbase/qmake/library/qmakebuiltins.cpp:540:22: note: in expansion of macro 'QT_POPEN'
  540 |     if (FILE *proc = QT_POPEN(QString(QLatin1String("cd ")
      |                      ^~~~~~~~

C:/qt5/qtbase/qmake/library/qmakebuiltins.cpp:78:19: error: '_pclose' was not declared in this scope; did you mean '_lclose'?
   78 | #define QT_PCLOSE _pclose
      |                   ^~~~~~~

C:/qt5/qtbase/qmake/library/qmakebuiltins.cpp:550:18: note: in expansion of macro 'QT_PCLOSE'
  550 |         int ec = QT_PCLOSE(proc);
      |                  ^~~~~~~~~

C:/qt5/qtbase/qmake/library/qmakebuiltins.cpp: In member function 'QMakeEvaluator::VisitReturn QMakeEvaluator::evaluateBuiltinExpand(const QMakeInternal::QMakeBuiltin&, const ProKey&, const ProStringList&, ProStringList&)':
C:/qt5/qtbase/qmake/library/qmakebuiltins.cpp:1241:25: error: 'KEY_WOW64_32KEY' was not declared in this scope
 1241 |                 flags = KEY_WOW64_32KEY;
      |                         ^~~~~~~~~~~~~~~

C:/qt5/qtbase/qmake/library/qmakebuiltins.cpp:1244:25: error: 'KEY_WOW64_64KEY' was not declared in this scope
 1244 |                 flags = KEY_WOW64_64KEY;
      |                         ^~~~~~~~~~~~~~~

Makefile:255: recipe for target 'qmakebuiltins.o' failed
mingw32-make: *** [qmakebuiltins.o] Error 1

While all the errors are an issue, I'm mainly concerned about the _popen one. Both windows.h and stdio.h have been #include'd, and I even upgraded my mingw install to try and fix the error, but not luck.

Has anyone encountered anything like this in their build/ know who to fix it?

Thanks

[jsulm]

@vega Do you use the MinGW console to compile (you will find it in Qt menu in Windows start menu)?
What exact MinGW version do you use?

[JonB]

@vega
I know nothing about MinGW. But _popen() etc. are "low-level" OS calls. Supplied under Linux, seems to be there from MSVC. But not necessarily MinGW. See e.g. https://stackoverflow.com/questions/46343789/cant-find-popen-and-pclose-with-windows-codeblocks-mingw-16-01, https://stackoverflow.com/questions/22166633/mingw-function-not-found-when-compiled-with-std-c11, https://github.com/boostorg/type_erasure/issues/16 for others reporting problem on _popen under MinGW.

[vega]

@jsulm It looks like I'm using MinGW version 7 - the exact install is mingw-w64-v7.0.0. I tried to compile it directly from the command line in VS code. I can't seem to see the Qt menu in my Windows start menu - is there another way to access it?

[Christian Ehrlicher]

I'm pretty sure you've msys in your PATH and therefore configure is picking up the wrong compiler.

[vega]

@Christian-Ehrlicher It looks like I have both MinGW and msvs2017 (from qt) in my PATH. Should I removed MinGW?

[Christian Ehrlicher]

It depends on what you want to sue to compile Qt - MSVC or MinGW - only one of them should be visible to configure when compiling Qt.
Why do you want to compile Qt at all?

[vega]

@Christian-Ehrlicher I'm building Stellarium from source, and I need Qt in order to do so.

[vega]

@Christian-Ehrlicher Also, when I try and combile with just MinGW in path, I get the same error. When I try and compile with just msvc, I get an error that says "Cannot detect host toolchain. Please use -platform. Aborting."

[vega]

Note to future visitors: I was unfortunately unable to fix the _popen error. I eventually just decided to download qt with the qt installer ( it wasn't working for me previously) and it seems to be ok now. If anyone else encounters this error, good luck!

[yasamson]

It is necessary to change the mingw version according to the table https://wiki.qt.io/MinGW.