Free Pascal Compiler (FPC, formerly named FPK Pascal, for program author Florian Paul Klämpfl, the name changed at the end of 1997) is a compiler for the closely related programming language dialects Pascal and Object Pascal. It is free software, released under the GNU General Public License. It supports its own Object Pascal dialect, and in varying amounts, the dialects of several other Pascal family compilers, including those of Turbo Pascal, Delphi, and some historic Macintosh compilers. The dialect is selected on a per-unit (module) basis, and more than one dialect can be used to produce one program. It follows a write once, compile anywhere philosophy, and is available for many CPU architectures and operating systems (see ). It supports integrated assembly language and an internal assembler in several dialects. Separate projects exist to facilitate developing cross-platform graphical user interface (GUI) applications, the most prominent one being the Lazarus integrated development environment (IDE).