From 4ff3f205408ff8bb413d69151105d301858136ba Mon Sep 17 00:00:00 2001 From: 卜部昌平 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 --- iseq.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'iseq.h') diff --git a/iseq.h b/iseq.h index 8e4b796be7..4e427f557c 100644 --- a/iseq.h +++ b/iseq.h @@ -1,3 +1,5 @@ +#ifndef RUBY_ISEQ_H +#define RUBY_ISEQ_H 1 /********************************************************************** iseq.h - @@ -8,9 +10,6 @@ Copyright (C) 2004-2008 Koichi Sasada **********************************************************************/ - -#ifndef RUBY_ISEQ_H -#define RUBY_ISEQ_H 1 #include "internal/gc.h" #include "vm_core.h" -- cgit v1.2.3