[Bug libstdc++/78870] Support std::filesystem on Windows

["development at jordi dot vilar.cat" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78870

Jordi Vilar <development at jordi dot vilar.cat> changed:

           What    |Removed                     |Added
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                 CC|                            |development at jordi dot vilar.cat

--- Comment #17 from Jordi Vilar <development at jordi dot vilar.cat> ---
I think the patch is not including the required changes in <fstream> in order
to properly handle path arguments. Specifically, both constructors and methods
open() need an additional overload taking const wchar_t*, as required per
specs:

30.9.1 Header <fstream> synopsis
[...]
3 In this subclause, member functions taking arguments of const
filesystem::path::value_type* are only be provided on systems where
filesystem::path::value_type (30.10.7) is not char. [ Note: These
functions enable class path support for systems with a wide native path
character type, such as wchar_t.
—end note ]

This involves methods:
basic_filebuf::open(const filesystem::path::value_type* s, ios_base::openmode
mode);
explicit basic_ifstream::basic_ifstream(const filesystem::path::value_type* s,
ios_base::openmode mode = ios_base::in);
void basic_ifstream::open(const filesystem::path::value_type* s,
ios_base::openmode mode = ios_base::in);
explicit basic_ofstream::basic_ofstream(const filesystem::path::value_type* s,
ios_base::openmode mode = ios_base::out);
void basic_ofstream::open(const filesystem::path::value_type* s,
ios_base::openmode mode = ios_base::out);
explicit basic_fstream::basic_fstream(const std::filesystem::path::value_type*
s, ios_base::openmode mode = ios_base::in|ios_base::out);
void basic_fstream::open(const std::filesystem::path::value_type* s,
ios_base::openmode mode = ios_base::in|ios_base::out);

I hope this helps