From cppreference.com
Defined in header
boolcreate_directory(conststd::filesystem::path&p); (1) (since C++17)boolcreate_directory(conststd::filesystem::path&p,std::error_code&ec)noexcept; (2) (since C++17)boolcreate_directory(conststd::filesystem::path&p,conststd::filesystem::path&existing_p); (3) (since C++17)boolcreate_directory(conststd::filesystem::path&p,conststd::filesystem::path&existing_p,std::error_code&ec)noexcept; (4) (since C++17)boolcreate_directories(conststd::filesystem::path&p); (5) (since C++17)boolcreate_directories(conststd::filesystem::path&p,std::error_code&ec); (6) (since C++17)1,2) Creates the directory p as if by POSIX
with a second argument of static_cast<int>(std::filesystem::perms::all) (the parent directory must already exist). If the function fails because p resolves to an existing directory, no error is reported. Otherwise on failure an error is reported.
3,4) Same as (1,2), 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, no attributes of existing_p are copied.
5,6) Executes (1,2) for every element of p that does not already exist. If p already exists, the function does nothing (this condition is not treated as an error).
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
true if a directory was newly created for the directory p resolves to, false otherwise.
Exceptions
Any overload not marked noexcept may throw
if memory allocation fails.
1,5) Throws
std::filesystem::filesystem_error
on underlying OS API errors, constructed with p as the first path argument and the OS error code as the error code argument.
2,6) Sets a std::error_code& parameter to the OS API error code if an OS API call fails, and executes ec.
() if no errors occur.
3) Throws
std::filesystem::filesystem_error
on underlying OS API errors, constructed with p as the first path argument, existing_p as the second path argument, and the OS error code as the error code argument.
4) Sets a std::error_code& parameter to the OS API error code if an OS API call fails, and executes ec.
() if no errors occur.
Notes
The attribute-preserving overload (3,4) is implicitly invoked by
when recursively copying directories. Its equivalent in boost.filesystem is
(with argument order reversed).
Example
Run this code
#include<cassert>#include<cstdlib>#include<filesystem>intmain(){std::filesystem::current_path(std::filesystem::temp_directory_path());// Basic usagestd::filesystem::create_directories("sandbox/1/2/a");std::filesystem::create_directory("sandbox/1/2/b");// Directory already exists (false returned, no error)assert(!std::filesystem::create_directory("sandbox/1/2/b"));// Permissions copying usagestd::filesystem::permissions("sandbox/1/2/b",std::filesystem::perms::others_all,std::filesystem::perm_options::remove);std::filesystem::create_directory("sandbox/1/2/c","sandbox/1/2/b");std::system("ls -l sandbox/1/2");std::system("tree sandbox");std::filesystem::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 sandbox └── 1 └── 2 ├── a ├── b └── c Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
DR Applied to Behavior as published Correct behavior
C++17 error if target already exists but is not a directory not error
C++17 error_code overload of create_directories marked noexcept but can allocate memory noexcept removed
C++17 creation failure caused by an existing non-directory file is not an error made error See also