Exclude qmath.h from build

gmk27

Hi, I have an app (compiled on msvc201x) which uses math.h from VS include path. While building, qmath.h is being auto-included and leading to lot of macro redefs. I did try some procedures on internet but didn't work for me.

Any help is appreciated...

Christian Ehrlicher

I can include math.h and qmath.h without getting any compiler warnings or errors here.
What Qt-version and MSVC compiler do you use?

This is working fine:

#include <math.h>
#include <qmath.h>

int main(int argc, char** argv)
{
	return 0;
}

The order of the both includes also don't matter.

gmk27

@Christian-Ehrlicher MSVC2013. Qt creator 4.14.2 Qt 5.15.2
the solution you suggested is tried already. That didn't work for me somehow.
Let me try once again and confirm.

Christian Ehrlicher

Qt5.15 can not be use with this ancient compiler: https://doc.qt.io/qt-5/supported-platforms.html

gmk27

oh okay that explains the problem I guess. I tried again. It didn't work. VS2019 is what you suggest right?

gmk27

@Christian-Ehrlicher said in Exclude qmath.h from build:

Qt5.15 can not be use with this ancient compiler: https://doc.qt.io/qt-5/supported-platforms.html

I have installed VS2019 now. With MSVC2013 I don't have errors. Now I have lot of errors with my previous warnings intact. It is between qmath.h and corecrt_math_defines.h. What could be the problem?

J.Hilk

@gmk27 can you post the actual wording of the errors?

The new one and the original one, I had a math.h related problem recently and I'm wondering if it could be similar

Christian Ehrlicher

@gmk27 said in Exclude qmath.h from build:

What could be the problem?

You're still using the old compiler I would guess.

gmk27

@Christian-Ehrlicher No buddy. I have uninstalled VS2013 before installing the 2019 version. It is not even in the KITS, I checked everything.

gmk27

@J-Hilk

C4005: M_E: Macro redefinition     -      corecrt_math_defines.h
see previous definition of M_E        -      qmath.h

And so on with all M_* defines. I have included math.h before qmath.h as suggested.

Christian Ehrlicher

Please also make sure that not an old WinSDK is installed and used.
The corecrt_math_defines.h must contain something like this:

#ifndef _MATH_DEFINES_DEFINED
    #define _MATH_DEFINES_DEFINED
    // Definitions of useful mathematical constants
    //
    // Define _USE_MATH_DEFINES before including <math.h> to expose these macro
    // definitions for common math constants.  These are placed under an #ifdef
    // since these commonly-defined names are not part of the C or C++ standards

qmath.h properly defines _USE_MATH_DEFINES (line 50)

gmk27

@Christian-Ehrlicher - Yes, I see there are proper guard checks in corecrt_math_defines.h. BTW I have Windows 10 SDK installed. I believe it is the latest one. I tried to reproduce the warnings by creating a new Qt project (as in your 1st reply to this post) but these warnings are not popped up, interestingly. Point to note is - these warnings are coming even if I don't include the <qmath.h> in my existing project. I have checked whole project it is nowhere included. In the new project it is just fine (with either files included or only one).

Where should I look exactly to fix this kind of issue?

Just to remind my platform - Qt 5.15 and MSVC2019 kit

VRonin

The only conflict I've ever seen in this real is related to min/max functions but it can be easily solved adding NOMINMAX to the preprocessor definitions.