Boost Filesystem Version 4

Version 4 is a significant revision of the Boost Filesystem library that makes its interface and behavior closer to std::filesystem that was introduced in C++17 and updated in the later standards. It removes the features that were deprecated in Version 3 and makes a number of breaking changes.

Users can select Boost.Filesystem v4 version by defining BOOST_FILESYSTEM_VERSION macro to 4 when compiling their code. There is no need to separately compile Boost.Filesystem for each library version — a single binary supports both v3 and v4. Users should avoid using both v3 and v4 in the same application as this can lead to subtle bugs.

Breaking changes

path::filename no longer returns root name or root directory if the path contains no other elements. For example, on Windows path("C:").filename() used to return "C:" and path("C:\").filename() used to return "\" and both will return an empty path now. This also affects path::stem and path::extension methods, as those are based on path::filename.
path::stem and path::extension no longer treat a filename that starts with a dot and has no other dots as an extension. Filenames starting with a dot are commonly treated as filenames with an empty extension. The leading dot is used to indicate a hidden file on most UNIX-like systems.

Distributed under the Boost Software License, Version 1.0. See www.boost.org/LICENSE_1_0.txt