From 56a90a2081379a5286edf0eea70aa2000e26c7f9 Mon Sep 17 00:00:00 2001 From: Nico Weber Date: Fri, 17 Jul 2015 14:16:03 -0700 Subject: [PATCH] Let GOOGLE_COMPILE_ASSERT use static_assert if available. The motivation is that gcc 4.8+ and clang trunk warn on unused local typedefs, which COMPILE_ASSERT adds. After this change, the warning will be happy at least in C++11 builds. static_assert also produces a slighly nicer diagnostic than the typedef method. https://github.com/google/re2/commit/eb93e8bc43ac8d05322fb3e9fc885898ad924f8a did the same change in re2. --- src/google/protobuf/stubs/macros.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/src/google/protobuf/stubs/macros.h b/src/google/protobuf/stubs/macros.h index eb38268e393b5..0e9a9ec198208 100644 --- a/src/google/protobuf/stubs/macros.h +++ b/src/google/protobuf/stubs/macros.h @@ -113,12 +113,13 @@ struct CompileAssert { } // namespace internal #undef GOOGLE_COMPILE_ASSERT +#if __cplusplus >= 201103L +#define GOOGLE_COMPILE_ASSERT(expr, msg) static_assert(expr, #msg) +#else #define GOOGLE_COMPILE_ASSERT(expr, msg) \ ::google::protobuf::internal::CompileAssert<(bool(expr))> \ msg[bool(expr) ? 1 : -1]; \ (void)msg - - // Implementation details of COMPILE_ASSERT: // // - COMPILE_ASSERT works by defining an array type that has -1 @@ -159,6 +160,7 @@ struct CompileAssert { // // This is to avoid running into a bug in MS VC 7.1, which // causes ((0.0) ? 1 : -1) to incorrectly evaluate to 1. +#endif // __cplusplus >= 201103L } // namespace protobuf } // namespace google