RFR: 8301302: Platform preferences API [v39]

[Michael Strauß]

On Wed, 6 Dec 2023 19:59:25 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

>> Yes. This is the copy-and-swap idiom, where the copy is made by using a pass-by-value parameter.
>
> I see.
> 
> I did happen to spot this compiler warning while compiling:
> 
> 
> .../VC/bin/x64/cl.exe /nologo /W3 /EHsc /c /DINLINE=__inline /DUNICODE /D_UNICODE /DWIN32 /DIAL /D_LITTLE_ENDIAN /DWIN32_LEAN_AND_MEAN /IC:/Users/kcr/dev/jdks/jdk-19.0.2/include /I.../jdk-19.0.2/include/win32 /O2 /MD /DNDEBUG -Imodules\javafx.graphics\build\gensrc\headers\javafx.graphics -Imodules\javafx.graphics\src\main\native-glass\win /Fomodules\javafx.graphics\build\native\glass\win\RoActivationSupport.obj modules\javafx.graphics\src\main\native-glass\win\RoActivationSupport.cpp
> VC\include\utility(103) : warning C4717: 'std::swap<RoException,0>': recursive on all control paths, function will cause runtime stack overflow
> modules\javafx.graphics\src\main\native-glass\win\RoActivationSupport.cpp(233) : warning C4717: 'RoException::operator=': recursive on all control paths, function will cause runtime stack overflow
> 
> 
> you can see that in your GHA build as well. I don't know for certain whether this is a problem in practice or not, but it would be good to eliminate the warning.

I can fix this by swapping the `message_` fields directly, which doesn't change the logic of the copy-and-swap.

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PR Review Comment: https://git.openjdk.org/jfx/pull/1014#discussion_r1417949026