From 4ff3f205408ff8bb413d69151105d301858136ba Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E5=8D=9C=E9=83=A8=E6=98=8C=E5=B9=B3?= Date: Fri, 10 Apr 2020 14:11:40 +0900 Subject: add #include guard hack According to MSVC manual (*1), cl.exe can skip including a header file when that: - contains #pragma once, or - starts with #ifndef, or - starts with #if ! defined. GCC has a similar trick (*2), but it acts more stricter (e. g. there must be _no tokens_ outside of #ifndef...#endif). Sun C lacked #pragma once for a looong time. Oracle Developer Studio 12.5 finally implemented it, but we cannot assume such recent version. This changeset modifies header files so that each of them include strictly one #ifndef...#endif. I believe this is the most portable way to trigger compiler optimizations. [Bug #16770] *1: https://docs.microsoft.com/en-us/cpp/preprocessor/once *2: https://gcc.gnu.org/onlinedocs/cppinternals/Guard-Macros.html --- include/ruby/3/static_assert.h | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'include/ruby/3/static_assert.h') diff --git a/include/ruby/3/static_assert.h b/include/ruby/3/static_assert.h index 78ce4def4b..b9c842f3b6 100644 --- a/include/ruby/3/static_assert.h +++ b/include/ruby/3/static_assert.h @@ -1,4 +1,6 @@ -/** \noop-*-C++-*-vi:ft=cpp +#ifndef RUBY3_STATIC_ASSERT_H /*-*-C++-*-vi:se ft=cpp:*/ +#define RUBY3_STATIC_ASSERT_H +/** * @file * @author Ruby developers * @copyright This file is a part of the programming language Ruby. @@ -22,10 +24,7 @@ #include "ruby/3/has/extension.h" /** @cond INTERNAL_MACRO */ -#if defined(RUBY3_STATIC_ASSERT0) -# /* Take that. */ - -#elif defined(__cplusplus) && defined(__cpp_static_assert) +#if defined(__cplusplus) && defined(__cpp_static_assert) # /* https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations */ # define RUBY3_STATIC_ASSERT0 static_assert @@ -62,10 +61,7 @@ * @param expr Expression to assert. * @note `name` shall not be a string literal. */ -#if defined(RUBY3_STATIC_ASSERT) -# /* Take that. */ - -#elif defined(__DOXYGEN__) +#if defined(__DOXYGEN__) # define RUBY3_STATIC_ASSERT static_assert #elif defined(RUBY3_STATIC_ASSERT0) @@ -76,3 +72,5 @@ # define RUBY3_STATIC_ASSERT(name, expr) \ typedef int static_assert_ ## name ## _check[1 - 2 * !(expr)] #endif + +#endif /* RUBY3_STATIC_ASSERT_H */ -- cgit v1.2.3