Pthreads-win32 (a.k.a. pthreads4w) is an Open Source Software implementation of the Threads component of the POSIX 1003.1c 1995 Standard (or later) for Microsoft's Windows environment. Some functions from POSIX 1003.1b are also supported, including semaphores. Other related functions include the set of read-write lock functions. The library also supports some of the functionality of the Open Group's Single Unix specification, namely mutex types, plus some common and pthreads-win32 specific non-portable routines (see README.NONPORTABLE).

See the file "ANNOUNCE" for more information including standards conformance details and the list of supported and unsupported
routines.