[v3] Handle C++11 <math.h> overloads on Solaris 12

Rainer Orth ro@CeBiTec.Uni-Bielefeld.DE
Tue Nov 24 13:29:00 GMT 2015

Jonathan Wakely <jwakely@redhat.com> writes:

> On 24/11/15 13:32 +0100, Rainer Orth wrote:
>>Jonathan Wakely <jwakely@redhat.com> writes:
>>> On 17/11/15 13:33 +0100, Rainer Orth wrote:
>>>>Solaris 12 recently introduced the C++11 <math.h> overloads, which
>>>>caused bootstrap to be broken on both mainline and the gcc-5 branch:
>>>>In file included from /vol/gcc/src/hg/trunk/local/libstdc++-v3/include/precompiled/stdc++.h:41:0:
>>>>/var/gcc/regression/trunk/12-gcc/build/i386-pc-solaris2.12/libstdc++-v3/include/cmath: In function 'constexpr int std::fpclassify(float)':
>>>>/var/gcc/regression/trunk/12-gcc/build/i386-pc-solaris2.12/libstdc++-v3/include/cmath:561:3: error: redefinition of 'constexpr int std::fpclassify(float)'
>>>>   fpclassify(float __x)
>>>>   ^
>>>>In file included from /usr/include/math.h:13:0,
>>>>                 from /var/gcc/regression/trunk/12-gcc/build/i386-pc-solaris2.12/libstdc++-v3/include/cmath:44,
>>>>                 from /vol/gcc/src/hg/trunk/local/libstdc++-v3/include/precompiled/stdc++.h:41:
>>>>/usr/include/iso/math_c99.h:647:13: note: 'int std::fpclassify(float)' previously defined here
>>>>  inline int fpclassify(float __X) { return __builtin_fpclassify(
>>>>             ^
>>>>The following patch fixes this by testing for the problem and wrapping
>>>>the overloads in include/c_global/cmath and include/tr1/cmath
>>>>appropriately.  The test needs to be dynamic since apparently a backport
>>>>to Solaris 11 (and perhaps even Solaris 10) is planned.
>>> Why does <tr1/cmath> need to change, did Solaris also define the
>>> functions in namespace std::tr1?
>>Without that part, I get errors like
>>In file included from
>> /vol/gcc/src/hg/trunk/local/libstdc++-v3/include/precompiled/stdtr1c++.h:37:0:
>> In function 'float std::tr1::acosh(float)':
>> error: 'float std::tr1::acosh(float)' conflicts with a previous
>> declaration
>>   acosh(float __x)
> Ah yes, because there's a using std::acosh, which puts Solaris' new
> overloads into namespace std::tr1.
> OK, that's correct then, and the patch is OK for trunk and
> gcc-5-branch as far as I'm concerned.

Thanks.  I've installed the patch on both mainline and the gcc-5 branch
at once, rather than waiting for mainline soak time: in case there are
problems, it gives us more time to act on the branch this way.


Rainer Orth, Center for Biotechnology, Bielefeld University

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