std::experimental::filesystem::create_directory, (3) - Linux Manuals

std::experimental::filesystem::create_directory,: std::experimental::filesystem::create_directory,

NAME

std::experimental::filesystem::create_directory, - std::experimental::filesystem::create_directory,

Synopsis

Defined in header <experimental/filesystem>
bool create_directory( const path& p );                          (1) (filesystem TS)
bool create_directory( const path& p, error_code& ec );
bool create_directory( const path& p, const path& existing_p );
bool create_directory( const path& p, const path& existing_p,    (2) (filesystem TS)
error_code& ec );
bool create_directories( const path& p );                        (3) (filesystem TS)
bool create_directories( const path& p, error_code& ec );

1) Creates the directory p as if by POSIX mkdir() with a second argument of
static_cast<int>(fs::perms::all) (the parent directory must already exist). If p
already exists and is already a directory, the function does nothing (this condition
is not treated as an error).
2) Same as (1), except that the attributes of the new directory are copied from
existing_p (which must be a directory that exists). It is OS-dependent which
attributes are copied: on POSIX systems, the attributes are copied as if by

 stat(existing_p.c_str(), &attributes_stat)
 mkdir(p.c_str(), attributes_stat.st_mode)

On Windows OS, the attributes are copied as if by

 CreateDirectoryExW(existing_p.c_str(), p.c_str(), 0)

3) Executes (1) for every element of p that does not already exist.

The non-throwing overloads return false if any error occurs.

Parameters

p          - the path to the new directory to create
existing_p - the path to a directory to copy the attributes from
ec         - out-parameter for error reporting in the non-throwing overload

Return value

1,2) true if directory creation is successful, false otherwise.

Exceptions

1,3) The overload that does not take a error_code& parameter throws filesystem_error
on underlying OS API errors, constructed with p as the first argument and the OS
error code as the error code argument. std::bad_alloc may be thrown if memory
allocation fails. The overload taking a error_code& parameter sets it to the OS API
error code if an OS API call fails, and executes ec.clear() if no errors occur. This
overload has
noexcept specification:
noexcept
2) The overload that does not take a error_code& parameter throws filesystem_error
on underlying OS API errors, constructed with p as the first argument, existing_p as
the second argument, and the OS error code as the error code argument.
std::bad_alloc may be thrown if memory allocation fails. The overload taking a
error_code& parameter sets it to the OS API error code if an OS API call fails, and
executes ec.clear() if no errors occur. This overload has
noexcept specification:
noexcept

Notes

The attribute-preserving overload (2) is implicitly invoked by copy() when
recursively copying directories. Its equivalent in boost.filesystem is
copy_directory (with argument order reversed)

Example

// Run this code

 #include <iostream>
 #include <fstream>
 #include <cstdlib>
 #include <experimental/filesystem>
 namespace fs = std::experimental::filesystem;

 int main()
 {
  fs::create_directories("sandbox/1/2/a");
  fs::create_directory("sandbox/1/2/b");
  fs::permissions("sandbox/1/2/b", fs::perms::remove_perms | fs::perms::others_all);
  fs::create_directory("sandbox/1/2/c", "sandbox/1/2/b");
  std::system("ls -l sandbox/1/2");
  fs::remove_all("sandbox");
 }

Possible output:

 drwxr-xr-x 2 user group 4096 Apr 15 09:33 a
 drwxr-x--- 2 user group 4096 Apr 15 09:33 b
 drwxr-x--- 2 user group 4096 Apr 15 09:33 c