31 Input/output library [input.output]

31.12 File systems [filesystems]

31.12.13 Filesystem operation functions [fs.op.funcs]

31.12.13.8 Create directory [fs.op.create.directory]

bool filesystem::create_directory(const path& p); bool filesystem::create_directory(const path& p, error_code& ec) noexcept;
Effects: Creates the directory p resolves to, as if by POSIX mkdir with a second argument of static_cast<int>(perms​::​all).
If mkdir fails because p resolves to an existing directory, no error is reported.
Otherwise on failure an error is reported.
Returns: true if a new directory was created, otherwise false.
Throws: As specified in [fs.err.report].
bool filesystem::create_directory(const path& p, const path& existing_p); bool filesystem::create_directory(const path& p, const path& existing_p, error_code& ec) noexcept;
Effects: Creates the directory p resolves to, with attributes copied from directory existing_p.
The set of attributes copied is operating system dependent.
If mkdir fails because p resolves to an existing directory, no error is reported.
Otherwise on failure an error is reported.
[Note 1: 
For POSIX-based operating systems, the attributes are those copied by native API stat(existing_p.c_str(), &attributes_stat) followed by mkdir(p.c_str(), attributes_stat.st_mode).
For Windows-based operating systems, the attributes are those copied by native API CreateDirectoryExW(existing_p.c_str(), p.c_str(), 0).
— end note]
Returns: true if a new directory was created with attributes copied from directory existing_p, otherwise false.
Throws: As specified in [fs.err.report].