[Bug libstdc++/110653] Support std::stoi etc. without C99 APIs

["dave.anglin at bell dot net" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110653

--- Comment #6 from dave.anglin at bell dot net ---
On 2023-07-13 1:09 p.m., redi at gcc dot gnu.org wrote:
> I'm testing this, which should define std::stof and std::stold for hpux11.11:
>
> --- a/libstdc++-v3/include/bits/basic_string.h
> +++ b/libstdc++-v3/include/bits/basic_string.h
> @@ -4148,12 +4148,14 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
>     stod(const string& __str, size_t* __idx = 0)
>     { return __gnu_cxx::__stoa(&std::strtod, "stod", __str.c_str(), __idx); }
>
> -#if _GLIBCXX_USE_C99_STDLIB
> +#if _GLIBCXX_USE_C99_STDLIB || _GLIBCXX_HAVE_STRTOF
>     // NB: strtof vs strtod.
>     inline float
>     stof(const string& __str, size_t* __idx = 0)
>     { return __gnu_cxx::__stoa(&std::strtof, "stof", __str.c_str(), __idx); }
> +#endif
>
> +#if _GLIBCXX_USE_C99_STDLIB || _GLIBCXX_HAVE_STRTOLD
>     inline long double
>     stold(const string& __str, size_t* __idx = 0)
>     { return __gnu_cxx::__stoa(&std::strtold, "stold", __str.c_str(), __idx); }
> @@ -4161,7 +4163,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
>     inline long double
>     stold(const string& __str, size_t* __idx = 0)
>     { return std::stod(__str, __idx); }
> -#endif // _GLIBCXX_USE_C99_STDLIB
> +#endif
We get this error with the above:

bash-5.1$ gcc/xg++ -Bgcc/ -o xxx xxx.cc
-I./hppa64-hp-hpux11.11/libstdc++-v3/include 
-I./hppa64-hp-hpux11.11/libstdc++-v3/include/hppa64-hp-hpux11.11
-I/home/dave/gnu/gcc/gcc/libstdc++-v3/libsupc++ 
-Lhppa64-hp-hpux11.11/libstdc++-v3/src/.libs -O2
In file included from ./hppa64-hp-hpux11.11/libstdc++-v3/include/string:54,
                  from xxx.cc:1:
./hppa64-hp-hpux11.11/libstdc++-v3/include/bits/basic_string.h: In function
'long double std::__cxx11::stold(const std::string&, std::size_t*)':
./hppa64-hp-hpux11.11/libstdc++-v3/include/bits/basic_string.h:4161:36: error:
'strtold' is not a member of 'std'; did you mean 'strtoll'?
  4161 |   { return __gnu_cxx::__stoa(&std::strtold, "stold", __str.c_str(),
__idx); }
       |                                    ^~~~~~~
       |                                    strtoll