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Re: 2.0.11 on OS X 10.9 / Xcode 5.1
From: |
Taylan Ulrich Bayirli/Kammer |
Subject: |
Re: 2.0.11 on OS X 10.9 / Xcode 5.1 |
Date: |
Tue, 22 Apr 2014 16:36:41 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) |
Mark H Weaver <address@hidden> writes:
> What does (sin -0.0) evaluate to?
>
> My first guess is that at the C level, sin(-0.0) => 0.0 on your system,
> although IEEE 754 and C11 (F.10.1.6) specify that sin(-0.0) => -0.0.
>
> If my guess is incorrect, then please put a breakpoint in
> 'scm_c_make_polar' and see what's going wrong. Both 'ang' and 's'
> should be -0.0, and then it should pass -0.0 as the second argument to
> 'scm_c_make_rectangular'.
>
> Thanks,
> Mark
Update:
(As mentioned on IRC, (sin -0.0) evaluates to -0.0, also via sin() on
the C level in a minimal test-case compiled with the same compiler.
However...)
While trying to get the MacPorts-provided GCC 4.8 to build Guile with
debugging symbols (and not succeeding), I noticed that adding -g or
-ggdb to CFLAGS hides the issue, making address@hidden => 1.0-0.0i. It seems to
be enough to recompile numbers.c (I touch it and re-run make with or
without CFLAGS+="-g").
Interestingly even with -g or -ggdb the ".debug_info" of the installed
guile executable is empty as per dwarfdump(1). I wonder if, by the time
I actually manage to build with debug symbols, I'll be able to reproduce
the bug.
I wonder if I should concentrate on getting Guile to build with the
native compiler of OS X 10.9 / Xcode 5.1 instead (clang). I don't have
too much time for Guile at work anyway, and otherwise no OS X system.
Taylan