Specify __cdecl on main/wmain, as required by x86 (fixes #2486).

[davidmatson]

No description provided.

[codecov]

Codecov Report

Merging #2487 (b12c7a8) into v2.x (20d413b) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             v2.x    #2487   +/-   ##
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  Coverage   90.08%   90.08%           
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  Files         113      113           
  Lines        5040     5040           
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  Hits         4540     4540           
  Misses        500      500           

[horenmar]

I was gonna say that I am surprised this passes CI, but v2 used to use travis for non-Windows CI and that is dead.

Sprinkling __cdecl around will not compile with non-MSVC compilers, so it will need to be conditional. Alternatively, the warning that causes the compilation failure with /WX can be supressed.

[davidmatson]

Sprinkling __cdecl around will not compile with non-MSVC compilers, so it will need to be conditional.

Done - thanks for taking a look!

[dimztimz]

IMO it would be a good idea to additionally constrain this even more to just 32bit x86 with the predefined macro _M_IX86.

_M_IX86 Defined as the integer literal value 600 for compilations that target x86 processors. This macro isn't defined for x64 or ARM compilation targets.

[davidmatson]

I believe the convention, when specifying __cdecl, is always to specify it though rather than making it arch-specific. (I believe the requirement is for all architectures, it's just technically no different on some so it doesn't cause a problem in practice if it's not there.)

For example:
"On ARM and x64 processors, __cdecl is accepted but typically ignored by the compiler."
https://docs.microsoft.com/en-us/cpp/cpp/cdecl?view=msvc-170