PTLib is a moderately large C++ class library that originated many years
ago as a method to produce applications that run on both Microsoft
Windows and Unix X-Windows systems. It also was to have a Macintosh port
as well, but this never eventuated. In those days it was called the
PWLib the Portable Windows Library.

Since then, the availability of multi-platform GUI toolkits such as KDE
and wxWindows, and the development of the OpenH323 and OPAL projects as
primary user of the library, has emphasised the focus on networking, I/O
portability, multi-threading and protocol portability. Mostly, the
library is used to create high performance and highly portable
network-centric applications. So all the GUI abstractions ahave been
dropped and it was renamed the Portable Tools Library that you see
today.
