path: root/include/ruby/backward/rubyio.h
diff options
author卜部昌平 <>2020-04-10 14:11:40 +0900
committer卜部昌平 <>2020-04-13 16:06:00 +0900
commit4ff3f205408ff8bb413d69151105d301858136ba (patch)
tree0494fea3f4cdb82ec1d34e462438389dfea8b8da /include/ruby/backward/rubyio.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: *2:
Notes: Merged:
Diffstat (limited to 'include/ruby/backward/rubyio.h')
1 files changed, 12 insertions, 0 deletions
diff --git a/include/ruby/backward/rubyio.h b/include/ruby/backward/rubyio.h
index a6e3a7c78b..433f425988 100644
--- a/include/ruby/backward/rubyio.h
+++ b/include/ruby/backward/rubyio.h
@@ -1,6 +1,18 @@
+#ifndef RUBY_BACKWARD_RUBYIO_H /*-*-C++-*-vi:se ft=cpp:*/
+ * @file
+ * @author Ruby developers <>
+ * @copyright This file is a part of the programming language Ruby.
+ * Permission is hereby granted, to either redistribute and/or
+ * modify this file, provided that the conditions mentioned in the
+ * file COPYING are met. Consult the file for details.
+ */
#if defined __GNUC__
#warning use "ruby/io.h" instead of "rubyio.h"
#elif defined _MSC_VER
#pragma message("warning: use \"ruby/io.h\" instead of \"rubyio.h\"")
#include "ruby/io.h"