diff options
author | 卜部昌平 <shyouhei@ruby-lang.org> | 2020-04-10 14:11:40 +0900 |
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committer | 卜部昌平 <shyouhei@ruby-lang.org> | 2020-04-13 16:06:00 +0900 |
commit | 4ff3f205408ff8bb413d69151105d301858136ba (patch) | |
tree | 0494fea3f4cdb82ec1d34e462438389dfea8b8da /include/ruby/3/intern/time.h | |
parent | a3f6f67967644f34226b4424227d2eec52fedd45 (diff) |
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
Notes
Notes:
Merged: https://github.com/ruby/ruby/pull/3023
Diffstat (limited to 'include/ruby/3/intern/time.h')
-rw-r--r-- | include/ruby/3/intern/time.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/include/ruby/3/intern/time.h b/include/ruby/3/intern/time.h index d66d740679..a895bc0848 100644 --- a/include/ruby/3/intern/time.h +++ b/include/ruby/3/intern/time.h @@ -1,4 +1,6 @@ -/** \noop-*-C++-*-vi:ft=cpp +#ifndef RUBY3_INTERN_TIME_H /*-*-C++-*-vi:se ft=cpp:*/ +#define RUBY3_INTERN_TIME_H +/** * @file * @author Ruby developers <ruby-core@ruby-lang.org> * @copyright This file is a part of the programming language Ruby. @@ -16,10 +18,8 @@ * Do not expect for instance `__VA_ARGS__` is always available. * We assume C99 for ruby itself but we don't assume languages of * extension libraries. They could be written in C++98. - * @brief Public APIs related to ::rb_cStruct. + * @brief Public APIs related to ::rb_cTime. */ -#ifndef RUBY3_INTERN_TIME_H -#define RUBY3_INTERN_TIME_H #include "ruby/3/config.h" #ifdef HAVE_TIME_H |