fix(Clang CodeGen): remove warnings

[yumetodo]

./fmt/fmt/format.h(308,10): warning : unknown pragma ignored [-Wunknown-pragmas]
# pragma intrinsic(_BitScanReverse)
         ^
1 warning generated.
format.cc In file included from fmt\fmt\format.cc:28:
fmt\fmt/format.h(308,10): warning : unknown pragma ignored [-Wunknown-pragmas]
# pragma intrinsic(_BitScanReverse)
         ^
fmt\fmt\format.cc(165,17): warning : 'strerror' is deprecated: This
function or variable may be unsafe. Consider using strerror_s instead.
To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for
details. [-Wdeprecated-declarations]
      buffer_ = strerror(error_code_);
                ^
C:\Program Files (x86)\Windows Kits\10\Include\10.0.10240.0\ucrt\string.h(178,24) :  note: 'strerror' has been explicitly marked deprecated here
_ACRTIMP char* __cdecl strerror(
                       ^
fmt\fmt\format.cc(78,37): warning : unused function 'strerror_s' [-Wunused-function]
static inline fmt::internal::Null<> strerror_s(char *, std::size_t, ...) {
                                    ^
3 warnings generated.

[vitaut]

Thanks a lot for the PR! Looks good but could you replace -Wunused-function suppression with calling the dummy strerror_s function as it is done for strerror_r in

fmt/fmt/format.cc

Line 175 in 933a33a

strerror_r(0, FMT_NULL, "");

? It is a bit cleaner an the compiler will optimize the call away.

[yumetodo]

@vitaut I've fixed that. However, it is too dirty to use dummy function call to remove -Wunused-function warnings. I think.

[foonathan]

I usually cast the function to void, like you would do for unused variables.

[vitaut]

I usually cast the function to void, like you would do for unused variables.

Like this

(void)strerror_s;

without actually calling it?

[foonathan]

Yes

[yumetodo]

@foonathan out of the question

1>format.cc
1>fmt\fmt\format.cc(187,5): error : address of overloaded function 'strerror_s' cannot be cast to type 'void'
1>          (void)strerror_s;
1>           ^~~~
1>fmt\fmt\format.cc(78,37) :  note: candidate function
1>static inline fmt::internal::Null<> strerror_s(char *, std::size_t, ...) {
1>                                    ^
1>C:\Program Files (x86)\Windows Kits\10\Include\10.0.10240.0\ucrt\string.h(183,14) :  note: candidate function
1>    errno_t, strerror_s,
1>             ^
1>C:\Program Files (x86)\Windows Kits\10\Include\10.0.10240.0\ucrt\string.h(41,30) :  note: candidate function
1>    _ACRTIMP errno_t __cdecl strerror_s(
1>                             ^
1>1 error generated.

[foonathan]

Yeah, okay ːD

[yumetodo]

We should consider [[maybe_unused]](C++17) or __attribute__ ((unused))(GCC extension)

#if FMT_HAS_CPP_ATTRIBUTE(maybe_unused)
# define FMT_HAS_CXX17_ATTRIBUTE_MAYBE_UNUSED
#elif defined(_MSVC_LANG) && _MSVC_LANG > 201402
# define FMT_HAS_CXX17_ATTRIBUTE_MAYBE_UNUSED
#endif

#ifdef FMT_HAS_CXX17_ATTRIBUTE_MAYBE_UNUSED
# define FMT_MAYBE_UNUSED [[maybe_unused]]
#elif defined(__GNUC__)
# define FMT_MAYBE_UNUSED __attribute__ ((unused))
#else
#define FMT_MAYBE_UNUSED
#endif

FMT_MAYBE_UNUSED static inline fmt::internal::Null<> strerror_s(char *, std::size_t, ...) {
  return fmt::internal::Null<>();
}

[vitaut]

We should consider [maybe_unused] or attribute ((unused))(GCC extension)

Good idea.

[yumetodo]

@vitaut implement in d2ba420 .

[vitaut]

Merged in 708d950, thanks!