Fix a warning which is treated as en error in Clang

[fengga]

I'm a dev from Microsoft and our product dependents on pevent. Recent changes will bring a warning and this warning in Clang is treated as an error:

uint32_t waitUnit = (WAIT_INFINITE - 1);

\deps\pevents\src\pevents.cpp(520,48): error : implicit conversion from 'unsigned long long' to 'uint32_t' (aka 'unsigned int') changes value from 18446744073709551614 to 4294967294 [-Werror,-Wconstant-conversion] [C:\MSAL3\microsoft-authentication-library-for-cpp_builds\vs-16-2019-win64-llvm-cxx17\source\msalsdk.vcxproj]

[mqudsi]

Hello @fengga and thanks for the PR.

I test against GCC9 and LLVM9 and didn't run into the conversion warning you're seeing, but then again, unsigned long long is 64-bits for me. I'm guessing you're compiling a 32-bit version of the library? I should probably add that to the CI.

[fengga]

Hello @fengga and thanks for the PR.

I test against GCC9 and LLVM9 and didn't run into the conversion warning you're seeing, but then again, unsigned long long is 64-bits for me. I'm guessing you're compiling a 32-bit version of the library? I should probably add that to the CI.

Hi @mqudsi, thanks for your quick response. I'm building a x64 lib using Clang 10.0.0 inside visual studio on Windows, and this issue is treated as an error (not a warning).

[mqudsi]

Interesting - thanks for the info.

I've merged the PR with a minor change to downcast before subtracting one in case any compilers still reason about truncation from 64-bits to 32-bits differently if it is all 0xFF. Thanks for filing!

[mqudsi]

@fengga I fixed one more downcast site and added a Windows target to the CI (I verified that CL reported the error as well); hopefully that'll catch it in the future.

Do you mind sharing what your team at MSFT is using this library for? I was previously only officially aware of its usage in Visual Studio Code.