GNAT is the GNU Ada Compiler based on GCC. The front-end and runtime are written in Ada.

The project started in 1992 when the US Air Force awarded the New York University (NYU) a contract to build an open source compiler for Ada to help with the Ada 9X standardization process. The contract required the use of the GNU GPL for all developments. In 1994 a company named Ada Core Technologies was founded to provide continuing development and commercial support of GNAT. The first official validation of GNAT happened in 1995. On October 2, 2001 the GNAT sources were contributed to the GCC CVS repository; they were previously released separately from the main GCC sources.

External Links