git / moonbite-core / src/libmw/deps/ghc/README.md · raw
[](https://travis-ci.org/gulrak/filesystem)[](https://ci.appveyor.com/project/gulrak/filesystem)[](https://cirrus-ci.com/github/gulrak/filesystem)[](https://cloud.drone.io/gulrak/filesystem)[](https://coveralls.io/github/gulrak/filesystem?branch=master)[](https://github.com/gulrak/filesystem/tree/v1.5.2)# FilesystemThis is a header-only single-file std::filesystem compatible helper library,based on the C++17 and C++20 specs, but implemented for C++11, C++14, C++17 or C++20(tightly following the C++17 standard with very few documented exceptions). It is currently tested onmacOS 10.12/10.14/10.15, Windows 10, Ubuntu 18.04, CentOS 7, CentOS 8, FreeBSD 12and Alpine ARM/ARM64 Linux but should work on other systems too, as long as you haveat least a C++11 compatible compiler. It should work with Android NDK, Emscripten and I evenhad reports of it being used on iOS (within sandboxing constraints).It is of course in its own namespace `ghc::filesystem` to not interfere with a regular `std::filesystem` should you use it in a mixed C++17environment (which is possible).*Test coverage is well above 90%, and starting with v1.3.6 and in v1.5.0more time was invested in benchmarking and optimizing parts of the library. I'll tryto continue to optimize some parts and refactor others, strivingto improve it as long as it doesn't introduce additional C++17/C++20 compatibilityissues. Feedback is always welcome. Simply open an issue if you see something missingor wrong or not behaving as expected and I'll comment.*## MotivationI'm often in need of filesystem functionality, mostly `fs::path`, but directoryaccess too, and when beginning to use C++11, I used that language updateto try to reduce my third-party dependencies. I could drop most of whatI used, but still missed some stuff that I started implementing for thefun of it. Originally I based these helpers on my own coding- and namingconventions. When C++17 was finalized, I wanted to use that interface,but it took a while, to push myself to convert my classes.The implementation is closely based on chapter 30.10 from the C++17 standardand a draft close to that version is[Working Draft N4687](https://github.com/cplusplus/draft/raw/master/papers/n4687.pdf).It is from after the standardization of C++17 but it contains the latest filesysteminterface changes compared to the[Working Draft N4659](https://github.com/cplusplus/draft/raw/master/papers/n4659.pdf).Staring with v1.4.0, when compiled using C++20, it adapts to the changes according to path sorting orderand `std::u8string` handling from [Working Draft N4860](https://isocpp.org/files/papers/N4860.pdf).I want to thank the people working on improving C++, I really liked how the languageevolved with C++11 and the following standards. Keep on the good work!## Why the namespace GHC?If you ask yourself, what `ghc` is standing for, it is simply`gulraks helper classes`, yeah, I know, not very imaginative, but I wanted ashort namespace and I use it in some of my private classes (so **it has nothingto do with Haskell**, sorry for the name clash).## Platforms`ghc::filesystem` is developed on macOS but CI tested on macOS, Windows,various Linux Distributions and FreeBSD. It should work on any of these with a C++11-capablecompiler. Also there are some checks to hopefully better work on Android, butas I currently don't test with the Android NDK, I wouldn't call it asupported platform yet, same is valid for using it with Emscripten. It is nowpart of the detected platforms, I fixed the obvious issues and ran some tests withit, so it should be fine. All in all, I don't see it replacing `std::filesystem`where full C++17 or C++20 is available, it doesn't try to be a "better"`std::filesystem`, just an almost drop-in if you can't use it (with the exceptionof the UTF-8 preference).:information_source: **Important:** _This implementation is following the ["UTF-8 Everywhere" philosophy](https://utf8everywhere.org/) in that all`std::string` instances will be interpreted the same as `std::u8string` encodingwise and as being in UTF-8. The `std::u16string` will be seen as UTF-16. See *Differences in API*for more information._Unit tests are currently run with:* macOS 10.12: Xcode 9.2 (clang-900.0.39.2), GCC 9.2, Clang 9.0, macOS 10.13: Xcode 10.1, macOS 10.14: Xcode 11.2, macOS 10.15: Xcode 11.6* Windows: Visual Studio 2017, Visual Studio 2015, Visual Studio 2019, MinGW GCC 6.3 (Win32), GCC 7.2 (Win64)* Linux (Ubuntu): GCC (5.5, 6.5, 7.4, 8.3, 9.2), Clang (5.0, 6.0, 7.1, 8.0, 9.0)* Linux (Alpine ARM/ARM64): GCC 9.2.0* FreeBSD: Clang 8.0## TestsThe header comes with a set of unit-tests and uses [CMake](https://cmake.org/)as a build tool and [Catch2](https://github.com/catchorg/Catch2) as test framework.All tests agains this implementation should succeed, depending on your environmentit might be that there are some warnings, e.g. if you have no rights to createSymlinks on Windows or at least the test thinks so, but these are just informative.To build the tests from inside the project directory under macOS or Linux just:```cppmkdir buildcd buildcmake -DCMAKE_BUILD_TYPE=Debug ..make```This generates `filesystem_test`, the binary that runs all tests.If the default compiler is a GCC 8 or newer, or Clang 7 or newer, itadditionally tries to build a version of the test binary compiled against GCCs/Clangs`std::filesystem` implementation, named `std_filesystem_test`as an additional test of conformance. Ideally all tests should compile andsucceed with all filesystem implementations, but in reality, there aresome differences in behavior, sometimes due to room for interpretation inin the standard, and there might be issues in these implementations too.## Usage### DownloadsThe latest release version is [v1.5.2](https://github.com/gulrak/filesystem/tree/v1.5.2) andsource archives can be found [here](https://github.com/gulrak/filesystem/releases/tag/v1.5.2).The latest pre-native-backend version is [v1.4.0](https://github.com/gulrak/filesystem/tree/v1.4.0) andsource archives can be found [here](https://github.com/gulrak/filesystem/releases/tag/v1.4.0).The latest pre-C++20-support release version is [v1.3.10](https://github.com/gulrak/filesystem/tree/v1.3.10) andsource archives can be found [here](https://github.com/gulrak/filesystem/releases/tag/v1.3.10).### Using it as Single-File-HeaderAs `ghc::filesystem` is at first a header-only library, it should be enough to copy the headeror the `include/ghc` directory into your project folder oder point your include path to this place andsimply include the `filesystem.hpp` header (or `ghc/filesystem.hpp` if you use the subdirectory).Everything is in the namespace `ghc::filesystem`, so one way to use it only asa fallback could be:```cpp#if ((defined(_MSVC_LANG) && _MSVC_LANG >= 201703L) || (defined(__cplusplus) && __cplusplus >= 201703L)) && defined(__has_include)#if __has_include(<filesystem>) && (!defined(__MAC_OS_X_VERSION_MIN_REQUIRED) || __MAC_OS_X_VERSION_MIN_REQUIRED >= 101500)#define GHC_USE_STD_FS#include <filesystem>namespace fs = std::filesystem;#endif#endif#ifndef GHC_USE_STD_FS#include <ghc/filesystem.hpp>namespace fs = ghc::filesystem;#endif```**Note that this code uses a two-stage preprocessor condition because Visual Studio 2015doesn't like the `(<...>)` syntax, even if it could cut evaluation early before. This code alsoused the minimum deployment target to detect if std::filesystem really is available on macOScompilation.****Note also, this detection now works on MSVC versions prior to 15.7 on, or without settingthe `/Zc:__cplusplus` compile switch that would fix `__cplusplus` on MSVC. (Without the switchthe compiler allways reports `199711L`([see](https://blogs.msdn.microsoft.com/vcblog/2018/04/09/msvc-now-correctly-reports-__cplusplus/)),but `_MSVC_LANG` works without it.**If you want to also use the `fstream` wrapper with `path` support as fallback,you might use:```cpp#if ((defined(_MSVC_LANG) && _MSVC_LANG >= 201703L) || (defined(__cplusplus) && __cplusplus >= 201703L)) && defined(__has_include)#if __has_include(<filesystem>) && (!defined(__MAC_OS_X_VERSION_MIN_REQUIRED) || __MAC_OS_X_VERSION_MIN_REQUIRED >= 101500)#define GHC_USE_STD_FS#include <filesystem>namespace fs {using namespace std::filesystem;using ifstream = std::ifstream;using ofstream = std::ofstream;using fstream = std::fstream;}#endif#endif#ifndef GHC_USE_STD_FS#include <ghc/filesystem.hpp>namespace fs {using namespace ghc::filesystem;using ifstream = ghc::filesystem::ifstream;using ofstream = ghc::filesystem::ofstream;using fstream = ghc::filesystem::fstream;} #endif```Now you have e.g. `fs::ofstream out(somePath);` and it is either the wrapper orthe C++17 `std::ofstream`.**Be aware, as a header-only library, it is not hiding the fact, that ituses system includes, so they "pollute" your global namespace. Use theforwarding-/implementation-header based approach (see below) to avoid this.**:information_source: **Hint:** There is an additional header named `ghc/fs_std.hpp` that implements thisdynamic selection of a filesystem implementation, that you can includeinstead of `ghc/filesystem.hpp` when you want std::filesystem whereavailable and ghc::filesystem where not.### Using it as Forwarding-/Implementation-HeaderAlternatively, starting from v1.1.0 `ghc::filesystem` can also be used byincluding one of two additional wrapper headers. These allow to includea forwarded version in most places (`ghc/fs_fwd.hpp`) while hiding theimplementation details in a single cpp that includes `ghc/fs_impl.hpp` toimplement the needed code. That way system includes are only visible frominside the cpp, all other places are clean.Be aware, that it is currently not supported to hide the implementationinto a Windows-DLL, as a DLL interface with C++ standard templates in interfacesis a different beast. If someone is willing to give it a try, I might integratea PR but currently working on that myself is not a priority.If you use the forwarding/implementation approach, you can still use the dynamicswitching like this:```cpp#if ((defined(_MSVC_LANG) && _MSVC_LANG >= 201703L) || (defined(__cplusplus) && __cplusplus >= 201703L)) && defined(__has_include)#if __has_include(<filesystem>) && (!defined(__MAC_OS_X_VERSION_MIN_REQUIRED) || __MAC_OS_X_VERSION_MIN_REQUIRED >= 101500)#define GHC_USE_STD_FS#include <filesystem>namespace fs {using namespace std::filesystem;using ifstream = std::ifstream;using ofstream = std::ofstream;using fstream = std::fstream;}#endif#endif#ifndef GHC_USE_STD_FS#include <ghc/fs-fwd.hpp>namespace fs {using namespace ghc::filesystem;using ifstream = ghc::filesystem::ifstream;using ofstream = ghc::filesystem::ofstream;using fstream = ghc::filesystem::fstream;} #endif```and in the implementation hiding cpp, you might use (before any include that includes `ghc/fs_fwd.hpp`to take precedence:```cpp#if ((defined(_MSVC_LANG) && _MSVC_LANG >= 201703L) || (defined(__cplusplus) && __cplusplus >= 201703L)) && defined(__has_include)#if __has_include(<filesystem>) && (!defined(__MAC_OS_X_VERSION_MIN_REQUIRED) || __MAC_OS_X_VERSION_MIN_REQUIRED >= 101500)#define GHC_USE_STD_FS#endif#endif#ifndef GHC_USE_STD_FS#define GHC_FILESYSTEM_IMPLEMENTATION#include <ghc/filesystem.hpp>#endif```:information_source: **Hint:** There are additional helper headers, named `ghc/fs_std_fwd.hpp` and`ghc/fs_std_impl.hpp` that use this technique, so you can simply include themif you want to dynamically select the filesystem implementation. they alsoenable the `wchar_t` support on `ghc::filesystem` on Windows, so the resultingimplementation in the `fs` namespace will be compatible.### Git Submodule and CMakeStarting from v1.1.0, it is possible to add `ghc::filesystem`as a git submodule, add the directory to your `CMakeLists.txt` with`add_subdirectory()` and then simply use `target_link_libraries(your-target ghc_filesystem)`to ensure correct include path that allow `#include <ghc/filesystem.hpp>`to work.The `CMakeLists.txt` offers a few options to customize its behaviour:* `GHC_FILESYSTEM_BUILD_TESTING` - Compile tests, default is `OFF` when used as a submodule, else `ON`.* `GHC_FILESYSTEM_BUILD_EXAMPLES` - Compile the examples, default is `OFF` when used as a submodule, else `ON`.* `GHC_FILESYSTEM_WITH_INSTALL` - Add install target to build, default is `OFF` when used as a submodule, else `ON`.### VersioningThere is a version macro `GHC_FILESYSTEM_VERSION` defined in case future changesmight make it needed to react on the version, but I don't plan to break anything.It's the version as decimal number `(major * 10000 + minor * 100 + patch)`.:information_source: **Note:** Only even patch versions will be used for releasesand odd patch version will only be used for in between commits while working onthe next version.## DocumentationThere is almost no documentation in this release, as any `std::filesystem`documentation would work, besides the few differences explained in the nextsection. So you might head over to https://en.cppreference.com/w/cpp/filesystemfor a description of the components of this library.When compiling with C++11, C++14 or C++17, the API is following the C++17standard, where possible, with the exception that `std::string_view` parametersare only supported on C++17. When Compiling with C++20, `ghc::filesysytem`defaults to the C++20 API, with the `char8_t` and `std::u8string` interfacesand the deprecated `fs::u8path` factory method.:information_source: **Note:** If the C++17 API should be enforced even in C++20 mode,use the define `GHC_FILESYSTEM_ENFORCE_CPP17_API`.Even then it is possible to create `fws::path` from `std::u8string` but`fs::path::u8string()` and `fs::path::generic_u8string()` return normalUTF-8 encoded `std::string` instances, so code written for C++17 couldstill work with `ghc::filesystem` when compiled with C++20.The only additions to the standard are documented here:### `ghc::filesystem::ifstream`, `ghc::filesystem::ofstream`, `ghc::filesystem::fstream`These are simple wrappers around `std::ifstream`, `std::ofstream` and `std::fstream`.They simply add an `open()` method and a constuctor with an `ghc::filesystem::path`argument as the `fstream` variants in C++17 have them.### `ghc::filesystem::u8arguments`This is a helper class that currently checks for UTF-8 encoding on non-Windows platforms but on Windows itfetches the command line arguments als Unicode strings from the OS with```cpp::CommandLineToArgvW(::GetCommandLineW(), &argc)```and then converts them to UTF-8, and replaces `argc` and `argv`. It is a guard-likeclass that reverts its changes when going out of scope.So basic usage is:```cppnamespace fs = ghc::filesystem;int main(int argc, char* argv[]){ fs::u8arguments u8guard(argc, argv); if(!u8guard.valid()) { std::cerr << "Bad encoding, needs UTF-8." << std::endl; exit(EXIT_FAILURE); } // now use argc/argv as usual, they have utf-8 enconding on windows // ... return 0;}```That way `argv` is UTF-8 encoded as long as the scope from `main` is valid.**Note:** On macOS, while debugging under Xcode the code currently will return`false` as Xcode starts the application with `US-ASCII` as encoding, no matter whatencoding is actually used and even setting `LC_ALL` in the product scheme doesn'tchange anything. I still need to investigate this.## DifferencesAs this implementation is based on existing code from my private helperclasses, it derived some constraints of it. Starting from v1.5.0 most of thedifferences between this and the standard C++17/C++20 API where removed.### LWG DefectsThis implementation has switchable behavior for the LWG defects[#2682](https://wg21.cmeerw.net/lwg/issue2682),[#2935](http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2935),[#2936](http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2936) and[#2937](http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2937).The currently selected behavior (starting from v1.4.0) is following[#2682](https://wg21.cmeerw.net/lwg/issue2682), [#2936](http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2936),[#2937](http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2937) butnot following [#2935](http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2935),as I feel it is a bug to report no error on a `create_directory()` or `create_directories()`where a regular file of the same name prohibits the creation of a directory and forcesthe user of those functions to double-check via `fs::is_directory` if it really worked.The more intuitive approach to directory creation of treating a file with that name as anerror is also advocated by the newer paper[WG21 P1164R0](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1164r0.pdf), the revisonP1161R1 was agreed upon on Kona 2019 meeting [see merge](https://github.com/cplusplus/draft/issues/2703)and GCC by now switched to following its proposal([GCC #86910](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86910)).### Not Implemented on C++ before C++17```cpp// methods in ghc::filesystem::path:path& operator+=(basic_string_view<value_type> x);int compare(basic_string_view<value_type> s) const;```These are not implemented under C++11 and C++14, as there is no`std::basic_string_view` available and I did want to keep thisimplementation self-contained and not write a full C++17-upgrade forC++11/14. Starting with v1.1.0 these are supported when compilingghc::filesystem under C++17 of C++20.Starting with v1.5.2 `ghc::filesystem` will try to allow the use of`std::experimental::basic_string_view` where it detects is availability.Additionally if you have a `basic_string_view` compatible c++11implementation it can be used instead of `std::basic_string_view`by defining `GHC_HAS_CUSTOM_STRING_VIEW` and importing theimplementation into the `ghc::filesystem` namespace with:```cppnamespace ghc { namespace filesystem { using my::basic_string_view; }}```before including the filesystem header.### Differences in APITo not depend on any external third party libraries and still stay portable andcompact, this implementation is following the ["UTF-8 Everywhere" philosophy](https://utf8everywhere.org/) in that all`std::string` instances will be interpreted the same as `std::u8string` encodingwise and as being in UTF-8. The `std::u16string` will be seen as UTF-16 and `std::u32string` will beseen as unicode codepoints. Depending on the size of `std::wstring` characters, it will handle`std::wstring` as being UTF-16 (e.g. Windows) or `char32_t` unicode codepoints(currently all other platforms).#### Differences of Specific InterfacesStarting with v1.5.0 `ghc::filesystem` is following the C++17 standard inusing `wchar_t` and `std::wstring` on Windows as the types internally usedfor path representation. It is still possible to get the old behavior by defining`GHC_WIN_DISABLE_WSTRING_STORAGE_TYPE` and get `filesystem::path::string_type` as`std::string` and `filesystem::path::value_type` as `wchar_t`.If you need to call some Windows API, with v1.5.0 and above, simplyuse the W-variant of the Windows-API call (e.g. `GetFileAttributesW(p.c_str())`).:information_source: **Note:** _When using the old behavior by defining`GHC_WIN_DISABLE_WSTRING_STORAGE_TYPE`, use the `path::wstring()` member(e.g. `GetFileAttributesW(p.wstring().c_str())`). This gives you theUnicode variant independant of the `UNICODE` macro and makes sharing codebetween Windows, Linux and macOS easier and works with `std::filesystem` and`ghc::filesystem`._```cppstd::string path::u8string() const;std::string path::generic_u8string() const;vs.std::u8string path::u8string() const;std::u8string path::generic_u8string() const;```The return type of these two methods is depending on the used C++ standardand if `GHC_FILESYSTEM_ENFORCE_CPP17_API` is defined. On C++11, C++14 andC++17 or when `GHC_FILESYSTEM_ENFORCE_CPP17_API` is defined, the returntype is `std::string`, and on C++20 without the define it is `std::u8string`.### Differences in BehaviorI created a wiki entry about quite a lot of [behavioral differences](https://github.com/gulrak/filesystem/wiki/Differences-to-Standard-Filesystem-Implementations)between different `std::filesystem` implementations that could result in amention here, but this readme only tries to address the design choicedifferences between `ghc::filesystem` and those. I try to update the wiki pagefrom time to time.Any additional observations are welcome!#### fs.path ([ref](https://en.cppreference.com/w/cpp/filesystem/path))Since v1.5.0 the complete inner mechanics of this implementations `fs::path` where changed to the _native_ format as the internal representation.Creating any mixed slash `fs::path` object under Windows (e.g. with `"C:\foo/bar"`)will lead clean path with `"C:\foo\bar"` via `native()` and `"C:/foo/bar"` via`generic_string()` API. On all platforms redundant additional separators areremoved, even if this is not enforced by the standard and other implementationsmostly not do this.Additionally this implementation follows the standards suggestion to handleposix paths of the form `"//host/path"` and USC path on windows also as havinga root-name (e.g. `"//host"`). The GCC implementation didn't choose to do thatwhile testing on Ubuntu 18.04 and macOS with GCC 8.1.0 or Clang 7.0.0. This differencewill show as warnings under std::filesystem. This leads to a change in thealgorithm described in the standard for `operator/=(path& p)` where any path`p` with `p.is_absolute()` will degrade to an assignment, while this implementationhas the exception where `*this == *this.root_name()` and `p == preferred_seperator`a normal append will be done, to allow:```cppfs::path p1 = "//host/foo/bar/file.txt";fs::path p2;for (auto p : p1) p2 /= p;ASSERT(p1 == p2);```For all non-host-leading paths the behaviour will match the one described bythe standard.## Open Issues### Windows#### Symbolic Links on WindowsAs symbolic links on Windows, while being supported more or less sinceWindows Vista (with some strict security constraints) and fully since some earlierbuild of Windows 10, when "Developer Mode" is activated, are at time of writing(2018) rarely used, still they are supported with this implementation.#### PermissionsThe Windows ACL permission feature translates badly to the POSIX permissionbit mask used in the interface of C++17 filesystem. The permissions returnedin the `file_status` are therefore currently synthesized for the `user`-leveland copied to the `group`- and `other`-level. There is still some potentialfor more interaction with the Windows permission system, but currently settingor reading permissions with this implementation will most certainly not leadto the expected behavior.## Release Notes### v1.5.3 (WIP)* Fix for [#107](https://github.com/gulrak/filesystem/issues/107), the error handling for status calls was suppressing errors on symlink targets. * Pull request [#106](https://github.com/gulrak/filesystem/issues/106), fixed detection of AppleClang for compile options.* Pull request [#105](https://github.com/gulrak/filesystem/issues/105), added option GHC_FILESYSTEM_BUILD_STD_TESTING to override additional build of `std::filesystem` versions of the tests for comparison and the possibility to use GHC_FILESYSTEM_TEST_COMPILE_FEATURES to prefill the used compile features defaulting to CMAKE_CXX_COMPILE_FEATURES when not given.### [v1.5.2](https://github.com/gulrak/filesystem/releases/tag/v1.5.2)* Enhancement [#104](https://github.com/gulrak/filesystem/issues/104), on POSIX backend: optimized reuse of status information and reduced `directory_entry` creation leads to about 20%-25% in tests with `recursive_directory_iterator` over a larger directory tree.* Pull request [#103](https://github.com/gulrak/filesystem/pull/103), `wchar_t` was not in the list of supported char types on non-Windows backends.* Pull request [#102](https://github.com/gulrak/filesystem/pull/102), improved `string_view` support makes use of `<string_view>` or `<experiemental/string_view>` when available, and allows use of custom `basic_string_view` implementation when defining `GHC_HAS_CUSTOM_STRING_VIEW` and importing the string view into the `ghc::filesystem` namespace before including filesystem header.* Pull request [#101](https://github.com/gulrak/filesystem/pull/101), fix for [#100](https://github.com/gulrak/filesystem/issues/100), append and concat type of operations on path called redundant conversions.* Pull request [#98](https://github.com/gulrak/filesystem/pull/98), on older linux variants (GCC 7/8), the comerative `std::filesystem` tests now link with `-lrt` to avoid issues.* Fix for [#97](https://github.com/gulrak/filesystem/issues/97), on BTRFS the test case for `fs::hard_link_count` failed due to the filesystems behavior, the test case was adapted to take that into account.* Pull request [#96](https://github.com/gulrak/filesystem/pull/96), the export attribute defines `GHC_FS_API` and `GHC_FS_API_CLASS` are now honored when when set from outside to allow override of behavior.* Fix for [#95](https://github.com/gulrak/filesystem/issues/95), the syntax for disabling the deprecated warning in tests in MSVC was wrong.* Pull request [#93](https://github.com/gulrak/filesystem/pull/93), now the CMake configuration file is configured and part of the `make install` files.### [v1.5.0](https://github.com/gulrak/filesystem/releases/tag/v1.5.0)* Fix for [#91](https://github.com/gulrak/filesystem/issues/91), the way the CMake build options `GHC_FILESYSTEM_BUILD_TESTING`, `GHC_FILESYSTEM_BUILD_EXAMPLES` and `GHC_FILESYSTEM_WITH_INSTALL` where implemented, prohibited setting them from a parent project when using this via `add_subdirectory`, this fix allows to set them again.* Major refactoring for [#90](https://github.com/gulrak/filesystem/issues/90), the way, the Windows version of `fs::path` was originally created from the POSIX based implementation was, by adaption of the incoming and outgoing strings. This resulted in a mutable cache inside `fs::path`on Windows, that was inherently not thread-safe, even for `const` methods. To not add additional patches to a suboptimal solution, this time I reworked the `path` code to now store _native_ path-representation. This changed a lot of code, but when combined with `wchar_t` as `value_type` helped to avoid lots of conversion for calls to Win-API.<br> As interfaces where changed, it had to be released in a new minor version. The set of refactorings resulted in the following changes: * `fs::path::native()` and `fs::path::c_str()` can now be `noexcept` as the standard mandates * On Windows `wchar_t` is now the default for `fs::path::value_type` and `std::wstring` is the default f�r `fs::path::string_type`. * This allows the implementation to call Win-API without allocating conversions * Thread-safety on `const` methods of `fs::path` is no longer an issue * Some code could be simplified during this refactoring * Automatic prefixing of long path on Windows can now be disabled with defining `GHC_WIN_DISABLE_AUTO_PREFIXES`, for all other types of prefixes or namespaces the behavior follows that of MSVC `std::filesystem::path` * In case the old `char`/`std::string` based approach for Windows is still needed, it can be activated with `GHC_WIN_DISABLE_WSTRING_STORAGE_TYPE`* Enhancement for [#89](https://github.com/gulrak/filesystem/issues/89), `fs::file_status` now supports `operator==` introduced in `std::filesystem` with C++20.* Refactoring for [#88](https://github.com/gulrak/filesystem/issues/88), `fs::path::parent_path()` had a performance issue, as it was still using a loop based approach to recreate the parent from elements. This created lots of temporaries and was too slow especially on long paths.### [v1.4.0](https://github.com/gulrak/filesystem/releases/tag/v1.4.0)* Enhancements for [#71](https://github.com/gulrak/filesystem/issues/71), when compiled with C++20: * `char8_t` and `std::u8string` are supported where `Source` is the parameter type * `fs::path::u8string()` and `fs::path::generic_u8string()` now return a `std::u8string` * The _spaceship operator_ `<=>` is now supported for `fs::path` * With the define `GHC_FILESYSTEM_ENFORCE_CPP17_API` `ghc::filesystem` will fall back to the old `fs::path::u8string()` and `fs::path::generic_u8string()` API if preferred* Bugfix for `fs::proximate(p, ec)` where the internal call to `fs::current_path()` was not using the `error_code` variant, throwing possible exceptions instead of setting `ec`.* Enhancement `LWG_2936_BEHAVIOUR` is now on by default.* Some cleanup work to reduce preprocessor directives for better readability and remove unneeded template specializations.### [v1.3.10](https://github.com/gulrak/filesystem/releases/tag/v1.3.10)* Fix for [#81](https://github.com/gulrak/filesystem/issues/81), fixed issues with handling `Source` parameters that are string views.* Fix for [#79](https://github.com/gulrak/filesystem/issues/79), the bit operations for filesystem bitmasks that should be are now `constexpr`.### [v1.3.8](https://github.com/gulrak/filesystem/releases/tag/v1.3.8)* Refactoring for [#78](https://github.com/gulrak/filesystem/issues/78), the dynamic switching helper includes are now using `__MAC_OS_X_VERSION_MIN_REQUIRED` to ensure that `std::filesystem` is only selected on macOS if the deployment target is at least Catalina.* Bugfix for [#77](https://github.com/gulrak/filesystem/issues/77), the `directory_iterator` and the `recursive_directory_iterator` had an issue with the `skip_permission_denied` option, that leads to the inability to skip SIP protected folders on macOS.* Enhancement for [#76](https://github.com/gulrak/filesystem/issues/76), `_MSVC_LANG` is now used when available, additionally to `__cplusplus`, in the helping headers to allow them to work even when `/Zc:__cplusplus` is not used.* Bugfix for [#75](https://github.com/gulrak/filesystem/issues/75), NTFS reparse points to mapped volumes where handled incorrect, leading to `false` on `fs::exists` or not-found-errors on `fs::status`. Namespaced paths are not filtered anymore.### [v1.3.6](https://github.com/gulrak/filesystem/releases/tag/v1.3.6)* Pull request [#74](https://github.com/gulrak/filesystem/pull/74), on Windows symlink evaluation used the wrong reparse struct information and was not handling the case of relative paths well, thanks for the contribution.* Refactoring for [#73](https://github.com/gulrak/filesystem/issues/73), enhanced performance in path handling. the changes lead to much fewer path/string creations or copies, speeding up large directory iteration or operations on many path instances.* Bugfix for [#72](https://github.com/gulrak/filesystem/issues/72), the `TestAllocator` in `filesystem_test.cpp` was completed to fulfill the requirements to build on CentOS 7 with `devtoolset-9`. CentOS 7 and CentOS 8 are now part of the CI builds.* Bugfix for [#70](https://github.com/gulrak/filesystem/issues/70), root names are now case insensitive on Windows. This fix also adds the new behaviour switch `LWG_2936_BEHAVIOUR` that allows to enable post C++17 `fs::path::compare` behaviour, where the comparison is as if it was an element wise path comparison as described in [LWG 2936](https://cplusplus.github.io/LWG/issue2936) and C++20 `[fs.path.compare]`. It is default off in v1.3.6 and will be default starting from v1.4.0 as it changes ordering.### [v1.3.4](https://github.com/gulrak/filesystem/releases/tag/v1.3.4)* Pull request [#69](https://github.com/gulrak/filesystem/pull/69), use `wchar_t` versions of `std::fstream` from `ghc::filesystem::fstream` wrappers on Windows if using GCC with libc++.* Bugfix for [#68](https://github.com/gulrak/filesystem/issues/68), better handling of permission issues for directory iterators when using `fs::directory_options::skip_permission_denied` and initial support for compilation with emscripten.* Refactoring for [#66](https://github.com/gulrak/filesystem/issues/63), unneeded shared_ptr guards where removed and the file handles closed where needed to avoid unnecessary allocations.* Bugfix for [#63](https://github.com/gulrak/filesystem/issues/63), fixed issues on Windows with clang++ and C++17.* Pull request [#62](https://github.com/gulrak/filesystem/pull/62), various fixes for better Android support, thanks for the PR* Pull request [#61](https://github.com/gulrak/filesystem/pull/61), `ghc::filesystem` now supports use in projects with disabled exceptions. API signatures using exceptions for error handling are not available in this mode, thanks for the PR (this resolves [#60](https://github.com/gulrak/filesystem/issues/60) and [#43](https://github.com/gulrak/filesystem/issues/43))### [v1.3.2](https://github.com/gulrak/filesystem/releases/tag/v1.3.2)* Bugfix for [#58](https://github.com/gulrak/filesystem/issues/58), on MinGW the compilation could fail with an error about an undefined `ERROR_FILE_TOO_LARGE` constant.* Bugfix for [#56](https://github.com/gulrak/filesystem/issues/58), `fs::lexically_relative` didn't ignore trailing slash on the base parameter, thanks for PR [#57](https://github.com/gulrak/filesystem/pull/57).* Bugfix for [#55](https://github.com/gulrak/filesystem/issues/55), `fs::create_directories` returned `true` when nothing needed to be created, because the directory already existed.* Bugfix for [#54](https://github.com/gulrak/filesystem/issues/54), `error_code` was not reset, if cached result was returned.* Pull request [#53](https://github.com/gulrak/filesystem/pull/53), fix for wrong handling of leading whitespace when reading `fs::path` from a stream.* Pull request [#52](https://github.com/gulrak/filesystem/pull/52), an ARM Linux target is now part of the CI infrastructure with the service of Drone CI.* Pull request [#51](https://github.com/gulrak/filesystem/pull/51), FreeBSD is now part of the CI infrastucture with the service of Cirrus CI.* Pull request [#50](https://github.com/gulrak/filesystem/pull/50), adaptive cast to `timespec` fields to avoid warnings.### [v1.3.0](https://github.com/gulrak/filesystem/releases/tag/v1.3.0)* **Important: `ghc::filesystem` is re-licensed from BSD-3-Clause to MIT license.** (see [#47](https://github.com/gulrak/filesystem/issues/47))* Pull request [#46](https://github.com/gulrak/filesystem/pull/46), suppresses unused parameter warning on Android.* Bugfix for [#44](https://github.com/gulrak/filesystem/issues/44), fixes for warnings from newer Xcode versions.### [v1.2.10](https://github.com/gulrak/filesystem/releases/tag/v1.2.10)* The Visual Studio 2019 compiler, GCC 9.2 and Clang 9.0 where added to the CI configuration.* Bugfix for [#41](https://github.com/gulrak/filesystem/issues/41), `fs::rename` on Windows didn't replace an axisting regular file as required by the standard, but gave an error. New tests and a fix as provided in the issue was implemented.* Bugfix for [#39](https://github.com/gulrak/filesystem/issues/39), for the forwarding use via `fs_fwd.hpp` or `fs_std_fwd.hpp` der was a use of `DWORD` in the forwarding part leading to an error if `Windows.h` was not included before the header. The tests were changed to give an error in that case too and the useage of `DWORD` was removed.* Bugfix for [#38](https://github.com/gulrak/filesystem/issues/38), casting the return value of `GetProcAddress` gave a warning with `-Wcast-function-type` on MSYS2 and MinGW GCC 9 builds.### [v1.2.8](https://github.com/gulrak/filesystem/releases/tag/v1.2.8)* Pull request [#30](https://github.com/gulrak/filesystem/pull/30), the `CMakeLists.txt` will automatically exclude building examples and tests when used as submodule, the configuration options now use a prefixed name to reduce risk of conflicts.* Pull request [#24](https://github.com/gulrak/filesystem/pull/24), install target now creates a `ghcFilesystemConfig.cmake` in `${CMAKE_INSTALL_LIBDIR}/cmake/ghcFilesystem` for `find_package` that exports a target as `ghcFilesystem::ghc_filesystem`.* Pull request [#31](https://github.com/gulrak/filesystem/pull/31), fixes `error: redundant redeclaration of 'constexpr' static data member` deprecation warning in C++17 mode.* Pull request [#32](https://github.com/gulrak/filesystem/pull/32), fixes old-style-cast warnings.* Pull request [#34](https://github.com/gulrak/filesystem/pull/34), fixes [TOCTOU](https://en.wikipedia.org/wiki/Time-of-check_to_time-of-use) situation on `fs::create_directories`, thanks for the PR!* Feature [#35](https://github.com/gulrak/filesystem/issues/35), new CMake option to add an install target `GHC_FILESYSTEM_WITH_INSTALL` that is defaulted to OFF if `ghc::filesystem` is used via `add_subdirectory`.* Bugfix for [#33](https://github.com/gulrak/filesystem/issues/33), fixes an issue with `fs::path::lexically_normal()` that leaves a trailing separator in case of a resulting path ending with `..` as last element.* Bugfix for [#36](https://github.com/gulrak/filesystem/issues/36), warings on Xcode 11.2 due to unhelpfull references in path element iteration.### [v1.2.6](https://github.com/gulrak/filesystem/releases/tag/v1.2.6)* Pull request [#23](https://github.com/gulrak/filesystem/pull/23), tests and examples can now be disabled in CMake via seting `BUILD_TESTING` and `BUILD_EXAMPLES` to `NO`, `OFF` or `FALSE`.* Pull request [#25](https://github.com/gulrak/filesystem/pull/25), missing specialization for construction from `std::string_view` when available was added.* Additional test case when `std::string_view` is available.* Bugfix for [#27](https://github.com/gulrak/filesystem/issues/27), the `fs::path::preferred_seperator` declaration was not compiling on pre C++17 compilers and no test accessed it, to show the problem. Fixed it to an construction C++11 compiler should accept and added a test that is successful on all combinations tested.* Bugfix for [#29](https://github.com/gulrak/filesystem/issues/29), stricter warning settings where chosen and resulting warnings where fixed.### [v1.2.4](https://github.com/gulrak/filesystem/releases/tag/v1.2.4)* Enabled stronger warning switches and resulting fixed issues on GCC and MinGW* Bugfix for #22, the `fs::copy_options` where not forwarded from `fs::copy` to `fs::copy_file` in one of the cases.### [v1.2.2](https://github.com/gulrak/filesystem/releases/tag/v1.2.2)* Fix for ([#21](https://github.com/gulrak/filesystem/pull/21)), when compiling on Alpine Linux with musl instead of glibc, the wrong `strerror_r` signature was expected. The complex preprocessor define mix was dropped in favor of the usual dispatch by overloading a unifying wrapper.### [v1.2.0](https://github.com/gulrak/filesystem/releases/tag/v1.2.0)* Added MinGW 32/64 and Visual Studio 2015 builds to the CI configuration.* Fixed additional compilation issues on MinGW.* Pull request ([#13](https://github.com/gulrak/filesystem/pull/13)), set minimum required CMake version to 3.7.2 (as in Debian 8).* Pull request ([#14](https://github.com/gulrak/filesystem/pull/14)), added support for a make install target.* Bugfix for ([#15](https://github.com/gulrak/filesystem/issues/15)), the forward/impl way of using `ghc::filesystem` missed a `<vector>` include in the windows case.* Bugfix for ([#16](https://github.com/gulrak/filesystem/issues/16)), VS2019 didn't like the old size dispatching in the utf8 decoder, so it was changed to a sfinae based approach.* New feature ([#17](https://github.com/gulrak/filesystem/issues/17)), optional support for standard conforming `wchar_t/std::wstring` interface when compiling on Windows with defined `GHC_WIN_WSTRING_STRING_TYPE`, this is default when using the `ghc/fs_std*.hpp` header, to enhance compatibility.* New feature ([#18](https://github.com/gulrak/filesystem/issues/18)), optional filesystem exceptions/errors on unicode errors with defined `GHC_RAISE_UNICODE_ERRORS` (instead of replacing invalid code points or UTF-8 encoding errors with the replacement character `U+FFFD`).* Pull request ([#20](https://github.com/gulrak/filesystem/pull/20)), fix for file handle leak in `fs::copy_file`.* Coverage now checked in CI (~95% line coverage).### [v1.1.4](https://github.com/gulrak/filesystem/releases/tag/v1.1.4)* Additional Bugfix for ([#12](https://github.com/gulrak/filesystem/issues/12)), error in old unified `readdir/readdir_r` code of `fs::directory_iterator`; as `readdir_r` is now depricated, I decided to drop it and the resulting code is much easier, shorter and due to more refactoring faster* Fix for crashing unit tests against MSVC C++17 std::filesystem* Travis-CI now additionally test with Xcode 10.2 on macOS* Some minor refactorings### [v1.1.2](https://github.com/gulrak/filesystem/releases/tag/v1.1.2)* Bugfix for ([#11](https://github.com/gulrak/filesystem/issues/11)), `fs::path::lexically_normal()` had some issues with `".."`-sequences.* Bugfix for ([#12](https://github.com/gulrak/filesystem/issues/12)), `fs::recursive_directory_iterator` could run into endless loops, the methods depth() and pop() had issues and the copy behaviour and `input_iterator_tag` conformance was broken, added tests* Restructured some CMake code into a macro to ease the support for C++17 std::filesystem builds of tests and examples for interoperability checks.* Some fixes on Windows tests to ease interoperability test runs.* Reduced noise on `fs::weakly_canonical()` tests against `std::fs`* Added simple `du` example showing the `recursive_directory_iterator` used to add the sizes of files in a directory tree.* Added error checking in `fs::file_time_type` test helpers* `fs::copy()` now conforms LWG #2682, disallowing the use of `copy_option::create_symlinks' to be used on directories### [v1.1.0](https://github.com/gulrak/filesystem/releases/tag/v1.1.0)* Restructuring of the project directory. The header files are now using `hpp` as extension to be marked as c++ and they where moved to `include/ghc/` to be able to include by `<ghc/filesystem.hpp>` as the former include name might have been to generic and conflict with other files.* Better CMake support: `ghc::filesystem` now can be used as a submodul and added with `add_subdirectory` and will export itself as `ghc_filesystem` target. To use it, only `target_link_libraries(your-target ghc_filesystem)` is needed and the include directories will be set so `#include <ghc/filesystem.hpp>` will be a valid directive. Still you can simply only add the header file to you project and include it from there.* Enhancement ([#10](https://github.com/gulrak/filesystem/issues/10)), support for separation of implementation and forwarded api: Two additional simple includes are added, that can be used to forward `ghc::filesystem` declarations (`fs_fwd.hpp`) and to wrap the implementation into a single cpp (`fs_impl.hpp`)* The `std::basic_string_view` variants of the `fs::path` api are now supported when compiling with C++17.* Added CI integration for Travis-CI and Appveyor.* Fixed MinGW compilation issues.* Added long filename support for Windows.### [v1.0.10](https://github.com/gulrak/filesystem/releases/tag/v1.0.10)* Bugfix for ([#9](https://github.com/gulrak/filesystem/issues/9)), added missing return statement to `ghc::filesystem::path::generic_string()`* Added checks to hopefully better compile against Android NDK. There where no tests run yet, so feedback is needed to actually call this supported.* `filesystem.h` was renamed `filesystem.hpp` to better reflect that it is a c++ language header.### [v1.0.8](https://github.com/gulrak/filesystem/releases/tag/v1.0.8)* Bugfix for ([#6](https://github.com/gulrak/filesystem/issues/6)), where `ghc::filesystem::remove()` and `ghc::filesystem::remove_all()` both are now able to remove a single file and both will not raise an error if the path doesn't exist.* Merged pull request ([#7](https://github.com/gulrak/filesystem/pull/7)), a typo leading to setting error code instead of comparing it in `ghc::filesystem::remove()` under Windows.* Bugfix for (([#8](https://github.com/gulrak/filesystem/issues/8)), the Windows version of `ghc::filesystem::directory_iterator` now releases resources when reaching `end()` like the POSIX one does.### [v1.0.6](https://github.com/gulrak/filesystem/releases/tag/v1.0.6)* Bugfix for ([#4](https://github.com/gulrak/filesystem/issues/4)), missing error_code propagation in `ghc::filesystem::copy()` and `ghc::filesystem::remove_all` fixed.* Bugfix for ([#5](https://github.com/gulrak/filesystem/issues/5)), added missing std namespace in `ghc::filesystem::recursive_directory_iterator::difference_type`.### [v1.0.4](https://github.com/gulrak/filesystem/releases/tag/v1.0.4)* Bugfix for ([#3](https://github.com/gulrak/filesystem/issues/3)), fixed missing inlines and added test to ensure including into multiple implementation files works as expected.* Building tests with `-Wall -Wextra -Werror` and fixed resulting issues.### [v1.0.2](https://github.com/gulrak/filesystem/releases/tag/v1.0.2)* Updated catch2 to v2.4.0.* Refactored `fs.op.permissions` test to work with all tested `std::filesystem` implementations (gcc, clang, msvc++).* Added helper class `ghc::filesystem::u8arguments` as `argv` converter, to help follow the UTF-8 path on windows. Simply instantiate it with `argc` and `argv` and it will fetch the Unicode version of the command line and convert it to UTF-8. The destructor reverts the change.* Added `examples` folder with hopefully some usefull example usage. Examples are tested (and build) with `ghc::filesystem` and C++17 `std::filesystem` when available.* Starting with this version, only even patch level versions will be tagged and odd patch levels mark in-between non-stable wip states.* Tests can now also be run against MS version of std::filesystem for comparison.* Added missing `fstream` include.* Removed non-conforming C99 `timespec`/`timeval` usage.* Fixed some integer type mismatches that could lead to warnings.* Fixed `chrono` conversion issues in test and example on clang 7.0.0.### [v1.0.1](https://github.com/gulrak/filesystem/releases/tag/v1.0.1)* Bugfix: `ghc::filesystem::canonical` now sees empty path as non-existant and reports an error. Due to this `ghc::filesystem::weakly_canonical` now returns relative paths for non-existant argument paths. ([#1](https://github.com/gulrak/filesystem/issues/1))* Bugfix: `ghc::filesystem::remove_all` now also counts directories removed ([#2](https://github.com/gulrak/filesystem/issues/2))* Bugfix: `recursive_directory_iterator` tests didn't respect equality domain issues and dereferencable constraints, leading to fails on `std::filesystem` tests.* Bugfix: Some `noexcept` tagged methods and functions could indirectly throw exceptions due to UFT-8 decoding issues.* `std_filesystem_test` is now also generated if LLVM/clang 7.0.0 is found.### [v1.0.0](https://github.com/gulrak/filesystem/releases/tag/v1.0.0)This was the first public release version. It implements the full range ofC++17 std::filesystem, as far as possible without other C++17 dependencies.