> > Where it’s easy, prefer ‘static_assert’ to ‘verify’, > > Compiling a current GNU gettext with MSVC 14, I get this compilation error:
I got this working, by using preprocessor tricks, inspired by <https://github.com/Hirrolot/awesome-c-preprocessor> <https://stackoverflow.com/questions/11761703/> <https://groups.google.com/g/comp.std.c/c/d-6Mj5Lko_s?pli=1> <https://stackoverflow.com/questions/5134523/> 2022-09-14 Bruno Haible <br...@clisp.org> verify: Avoid syntax error due to static_assert with MSVC 14 in C++. * lib/verify.h (static_assert): For MSVC in C++ mode, use a definition that supports both the two-arguments and the one-argument syntax. diff --git a/lib/verify.h b/lib/verify.h index a0d597f3d4..0f5f0edc86 100644 --- a/lib/verify.h +++ b/lib/verify.h @@ -229,7 +229,22 @@ template <int w> # if (!defined static_assert \ && __STDC_VERSION__ < 202311 \ && __cpp_static_assert < 201411 && __GNUG__ < 6) -# define static_assert _Static_assert /* C11 requires this #define. */ +# if defined __cplusplus && _MSC_VER >= 1900 && !defined __clang__ +/* MSVC 14 in C++ mode supports the two-arguments static_assert but not + the one-argument static_assert, and it does not support _Static_assert. + We have to play preprocessor tricks to distinguish the two cases. + Since the MSVC preprocessor is not ISO C compliant (cf. + <https://stackoverflow.com/questions/5134523/>), the solution is specific + to MSVC. */ +# define _GL_EXPAND(x) x +# define _GL_SA1(a1) static_assert ((a1), "static assertion failed") +# define _GL_SA2 static_assert +# define _GL_SA3 static_assert +# define _GL_SA_PICK(x1,x2,x3,x4,...) x4 +# define static_assert(...) _GL_EXPAND(_GL_SA_PICK(__VA_ARGS__,_GL_SA3,_GL_SA2,_GL_SA1)) (__VA_ARGS__) +# else +# define static_assert _Static_assert /* C11 requires this #define. */ +# endif # endif #endif
