Error building opencv4 with qt5.15.2 tools

[FellowKrieger]

Hello, I am encoutering an error while trying to build opencv4 with qt tools.

Here are the versions used to create the build:
OpenCV4.8.0
Qt5.15.2 with the tools
gcc and g++ from mingw810_32

Description of the error:
in a directory set to receive the opencv build, I enter the command mingw32-make

at 96% the build stop with the error :

I am not sure what to do with the error.
I tried adding a couple of lines of code into the math.h file

#ifdef _WIN64
#define _hypot hypot
#include <cmath>
#endif

an advice I took from this post on on stackoverflow :
https://stackoverflow.com/questions/47735464/make-clean-not-working

but the mingw32-make still stopped at 96% afterwards.

Does somebody have some advice on this problem?

Thanks.

[jsulm]

@FellowKrieger What compiler version do you use and is C++11 or higher enabled?

[FellowKrieger]

@jsulm
compilation with gcc :
gcc version 7.3.0

How can I check if c++11 is enabled?

[jsulm]

@FellowKrieger said in Error building opencv4 with qt5.15.2 tools:

How can I check if c++11 is enabled?

By checking build log (compiler calls) or cmake output (assuming you're using CMake).

[FellowKrieger]

@jsulm Yes I am using CMake version 3.28.0. But I am not very familiar with it.

[Christian Ehrlicher]

set (CMAKE_CXX_STANDARD_REQUIRED 11)

See the cmake documentation.

[FellowKrieger]

@Christian-Ehrlicher I cleaned everything. Compiled with the qt tool mingw810_64 (MinGW-W64-builds-4.3.5, and compiler gcc version 7.3.0).
And It compiled until the end.

Looks like at first, I just picked the wrong compiler. I took at first mingw810_32.

Thanks also for the cmake instruction line. If necessary I will check this parameter.