48 lines
1.6 KiB
Diff
48 lines
1.6 KiB
Diff
From 01839b509c1bb914337124ac3d1f644b05ef90d8 Mon Sep 17 00:00:00 2001
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From: "Urabe, Shyouhei" <shyouhei@ruby-lang.org>
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Date: Tue, 5 Jun 2018 10:26:06 +0900
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Subject: [PATCH] C++11 is so bad it introduces a nightmare.
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TL;DR see https://developers.redhat.com/blog/2016/02/29/why-cstdlib-is-more-complicated-than-you-might-think/
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- `isnan` is something relatively new. We need to provide one for
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those systems without it. However:
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- X/Open defines `int isnan(double)`. Note the `int`.
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- C99 defines `isnan(x)` to be a macro.
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- C++11 nukes them all, undefines all the "masking macro"s, and
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define its own `bool isnan(double)`. Note the `bool`.
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- In C++, `int isnan(double)` and `bool isnan(double)` are
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incompatible.
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- So the mess.
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Signed-off-by: Urabe, Shyouhei <shyouhei@ruby-lang.org>
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---
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include/ruby/missing.h | 6 ++++++
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1 file changed, 6 insertions(+)
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diff --git a/include/ruby/missing.h b/include/ruby/missing.h
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index dc3fd502b5..8df917498e 100644
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--- include/ruby/missing.h.orig
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+++ include/ruby/missing.h
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@@ -168,6 +168,8 @@ RUBY_EXTERN const union bytesequence4_or_float rb_nan;
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# include <ieeefp.h>
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# endif
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# define isinf(x) (!finite(x) && !isnan(x))
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+# elif __cplusplus >= 201103L
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+# include <cmath> // it must include constexpr bool isinf(double);
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# else
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RUBY_EXTERN int isinf(double);
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# endif
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@@ -176,7 +178,11 @@ RUBY_EXTERN int isinf(double);
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#ifndef isnan
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# ifndef HAVE_ISNAN
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+# if __cplusplus >= 201103L
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+# include <cmath> // it must include constexpr bool isnan(double);
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+# else
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RUBY_EXTERN int isnan(double);
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+# endif
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# endif
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#endif
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--
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