Re: [PATCH] Preserve ::is{inf,nan}{f,l} prototypes even for C++11 and later

[Adhemerval Zanella <adhemerval dot zanella at linaro dot org>]

I will quote the email referenced:

> C++11 code using isinf and isnan continues to compile after that
> change, because the C++11 standard library provides its own versions
> conforming to the C++11 requirements. However, the C++11 library
> doesn't provide isinff, isinfl etc. and so code using those
> (non-standard) functions will no longer compile if they are not
> declared by glibc.

This was not clear to me, what kind of build issue are you seeing now?
Using isinf{f,l} by including just <cmath> along with C++11? If it is the
case please open a bugzilla (or update the original) and please commit
the fix.

Also, do we have a testcase on libstdc++ to catch this?

On 01-02-2016 14:34, Jonathan Wakely wrote:
> On 01/02/16 17:21 +0100, Jakub Jelinek wrote:
>> The recent changes disable not just ::is{inf,nan} prototypes that are
>> incompatible with C++11 and later and that are defined in <cmath> or
>> libstdc++ <math.h> wrapper, but also the ::is{inf,nan}{f,l} prototypes,
>> that are not incompatible with C++11.  This patch adds them back.
> 
> N.B. I also posted Jakub's patch at
> https://sourceware.org/ml/libc-alpha/2016-02/msg00020.html with some
> more context. The patch is the same though, so you can ignroe my
> duplicate.
> 
> 
>> ---
>> math/bits/mathcalls.h | 8 ++++++--
>> 1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/math/bits/mathcalls.h b/math/bits/mathcalls.h
>> index a48345d..1b82fcd 100644
>> --- a/math/bits/mathcalls.h
>> +++ b/math/bits/mathcalls.h
>> @@ -196,7 +196,9 @@ __MATHDECL_1 (int,__finite,, (_Mdouble_ __value)) __attribute__ ((__const__));
>> _Mdouble_END_NAMESPACE
>>
>> #ifdef __USE_MISC
>> -# if !defined __cplusplus || __cplusplus < 201103L /* Conflicts with C++11.  */
>> +# if (!defined __cplusplus \
>> +      || __cplusplus < 201103L /* isinf conflicts with C++11.  */ \
>> +      || __MATH_DECLARING_DOUBLE == 0) /* isinff or isinfl don't.  */
>> /* Return 0 if VALUE is finite or NaN, +1 if it
>>    is +Infinity, -1 if it is -Infinity.  */
>> __MATHDECL_1 (int,isinf,, (_Mdouble_ __value)) __attribute__ ((__const__));
>> @@ -232,7 +234,9 @@ __END_NAMESPACE_C99
>> __MATHDECL_1 (int,__isnan,, (_Mdouble_ __value)) __attribute__ ((__const__));
>>
>> #if defined __USE_MISC || (defined __USE_XOPEN && !defined __USE_XOPEN2K)
>> -# if !defined __cplusplus || __cplusplus < 201103L /* Conflicts with C++11.  */
>> +# if (!defined __cplusplus \
>> +      || __cplusplus < 201103L /* isinf conflicts with C++11.  */ \
>> +      || __MATH_DECLARING_DOUBLE == 0) /* isinff or isinfl don't.  */
>> /* Return nonzero if VALUE is not a number.  */
>> __MATHDECL_1 (int,isnan,, (_Mdouble_ __value)) __attribute__ ((__const__));
>> # endif
>> -- 
>> 2.4.3
>>