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author卜部昌平 <shyouhei@ruby-lang.org>2020-04-10 14:11:40 +0900
committer卜部昌平 <shyouhei@ruby-lang.org>2020-04-13 16:06:00 +0900
commit4ff3f205408ff8bb413d69151105d301858136ba (patch)
tree0494fea3f4cdb82ec1d34e462438389dfea8b8da /internal/proc.h
parenta3f6f67967644f34226b4424227d2eec52fedd45 (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 'internal/proc.h')
-rw-r--r--internal/proc.h6
1 files changed, 3 insertions, 3 deletions
diff --git a/internal/proc.h b/internal/proc.h
index aebaf28fb0..3d4c611584 100644
--- a/internal/proc.h
+++ b/internal/proc.h
@@ -1,4 +1,6 @@
-/** \noop-*-C-*-vi:ft=c
+#ifndef INTERNAL_PROC_H /*-*-C-*-vi:se ft=c:*/
+#define INTERNAL_PROC_H
+/**
* @file
* @author Ruby developers <ruby-core@ruby-lang.org>
* @copyright This file is a part of the programming language Ruby.
@@ -7,8 +9,6 @@
* file COPYING are met. Consult the file for details.
* @brief Internal header for Proc.
*/
-#ifndef INTERNAL_PROC_H
-#define INTERNAL_PROC_H
#include "ruby/ruby.h" /* for rb_block_call_func_t */
#include "ruby/st.h" /* for st_index_t */
struct rb_block; /* in vm_core.h */