Qt error while including <windows.h>

Question

How can I use windows.h in Qt application? After including it several errors like
"c:\Qt\4.4.3\include/QtCore/../../src/corelib/arch/qatomic_windows.h:387: error:
declaration of C function 'long int InterlockedCompareExchange(long int*, long int,
long int)' conflicts with
d:\old\mingw\bin../lib/gcc/mingw32/4.3.3/../../../../include/winbase.h:1681: error:
previous declaration 'LONG InterlockedCompareExchange(volatile LONG*, LONG,
LONG)' here"
appear.
All includes in order:
windows.h
iostream
QtCore
QtGui
QObject
QString
QFile
QProcess
QIODevice

EDIT: Problem disappear, Process.start() is now working, but I'm unable to say, what change made the difference. Thanks to all.

EDIT2: It's not that simple. I'll create new question.

EDIT3: The same code "QProcess Process; Process.start("notepad.exe");" works in main() and don't work in function called as a slot. Works only "QProcess *Process = new QProcess(); Process->start("notepad.exe");" I hate C++! Or should I hate Qt at the same time? It's 100 times simpler in Python. Literally, 100 times - several hours spent on various error messages. If only Python + Qt startup time were faster...

Answer 1

Use proper version of mingw for your version of Qt. Qt 4.3 is not compatible with mingw >= 4

Answer 2

Its worth debugging why QProcess throws a QProcess::UnknownError - switching to use the native API directly does make the whole point of using QT - its cross platform afterall - a bit of a joke.

You are doing something that should work, that probably uses WinExec or system() already and as such, your attempt to launch notepad will just fail again.

Perhaps QT just needs the full path to notepad.exe? There are definitely times to write platform code in QT, this isn't one of them.