-----Original Message-----
From: kmx Sent: Monday, November 25, 2013 8:41 AM To:
win32-vanilla@perl.org Subject: Re: FYI: quadmath.h's expq() crashes at
runtime
Hi Rob,
On 5.10.2013 17:06, sisyph...@optusnet.com.au wrote:
> Hi,
>
> It's no big deal, but current Strawberry Perl 32-bit and 64-bit
> compilers create executables that crash when expq() is called.
>
> Here's the minimalistic demo script:
>
> ####################
> #include <quadmath.h>
>
> int main (void) {
> __float128 r;
>
> r = expq(2.0Q);
> r = sqrtq(2.0Q);
> r = fabsq(2.0Q);
> r = sinq(2.0Q);
> r = logq(2.0Q);
> r = cosq(2.0Q);
>
> return 0;
> }
>
> ####################
>
> The resultant executable crashes when run, but remove the expq() call
> and there's no problem. (Link to -lquadmath when building the above
> program.)
>
> It's not just MinGW64's gcc-4.6.3 compilers that are affected. I find
> the same with their 64-bit gcc-4.7.0, and 4.8.1 compilers. (I haven't
> tested any other MinGW64 compilers.)
>
> I've also found that mingw.org's gcc-4.7.0 does *not* suffer this
> problem; nor does Ubuntu's gcc-4.6.3 ... so I guess I probably should
> report this to the mingw64 project.
>
> BTW, the perl relevance here is that, because of this bug,
> Math::Float128 crashes its test suite when expq() gets called. But I
> don't think that there's a high demand for this module, so I wouldn't be
> too concerned about that aspect.
I am afraid I cannot do much about expq crash unless there is newer
version of gcc and/or mingw-w64 runtime which does not suffer from this.
Yes - I subsequently reported the problem to the mingw64 mailing list, where
it was confirmed as a bug in their compilers.
I don't know when/if it will be fixed. I didn't actually file a bug report
anywhere - mainly because I don't know offhand where to file such a report,
and no-one replied when I asked about that on the mailing list.
In the meantime, I've changed the relevant XS code so that if
__MINGW64_VERSION_MAJOR is defined, instead of doing expq(p), it does
powq(e,p) - and that works fine.
>
> Also of slight relevance to Strawberry Perl is the fact that
> c/lib/gcc/[whatever]-w64-mingw32/4.6.3 is not in $Config{libpth}.
> As a consequence perl does not automatically find -lquadmath when the
> Math::Float128 Makefile.PL is run, and perl therefore removes the link.
> (The gcc linker can find -lquadmath without any help at all ... but it
> won't look for that library if perl has removed the link.)
As for this part you mean using something like this:
libpth='C:\strawberry\c\lib C:\strawberry\c\x86_64-w64-mingw32\lib
C:\strawberry\c\lib\gcc\x86_64-w64-mingw32\4.7.3'
right?
Yes - and similarly, for the 32-bit compiler, we want
C:\strawberry\c\lib\gcc\i686-w64-mingw32\4.7.3 added to libpth. (Not sure if
you're upgrading the compiler to "4.7.3" or whether you meant "4.6.3" ...
I'll find out soon enough ;-)
Cheers,
Rob
