Std::experimental::filesystem::create_directory, (3) Linux Manual Page

std::experimental::filesystem::create_directory,std::experimental::filesystem::create_directories – std::experimental::filesystem::create_directory,std::experimental::filesystem::create_directories

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);
(2)(filesystem TS)

    bool create_directory(const path &p, const path &existing_p, 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

std::experimental::filesystem::create_directory, (3) Linux Manual Page