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For other uses, see Gnat (disambiguation).
Ada source within GPS
Developer(s) AdaCore and the GNU Project
Stable release GNAT Pro 7.2.1 (2014-02-10)[1]
GNAT GPL 2014 (2014-03-31)
Operating system FreeBSD, GNU/Linux,
Microsoft Windows,
Mac OS X,
plus others as supported by GNAT-FSF within GCC
Type Compiler
License GNU GPL (compiler; GNAT GPL's runtime)
GMGPL (GNAT Pro's & GNAT-FSF's runtime)
Website GNAT Pro

GNAT is a free-software compiler for the Ada programming language which forms part of the GNU Compiler Collection. It supports all versions of the language, i.e. Ada 2012, Ada 2005, Ada 95 and Ada 83. Originally its name was an acronym that stood for GNU NYU Ada Translator, but that name no longer applies. The front-end and run-time are written in Ada.

JGNAT is a GNAT version that compiles from the Ada programming language to Java bytecode. GNAT for dotNET is a GNAT version that compiles from the Ada programming language to Common Language Infrastructure for the .NET Framework and the free and open source implementations Mono and Portable.NET.


The GNAT project started in 1992 when the United States Air Force awarded New York University (NYU) a contract to build a free compiler for Ada to help with the Ada 9X standardization process. The 3-million-dollar contract required the use of the GNU GPL for all development, and assigned the copyright to the Free Software Foundation. The first official validation of GNAT happened in 1995.

In 1994 and 1996, the original authors of GNAT founded two sister companies, Ada Core Technologies in New York City and ACT-Europe in Paris, to provide continuing development and commercial support of GNAT. The two companies merged as AdaCore in 2004.

GNAT was initially released separately from the main GCC sources. On October 2, 2001 the GNAT sources were contributed to the GCC CVS repository. The last version to be released separately was GNAT 3.15p, based on GCC 2.8.1, on October 2, 2002. Starting with GCC 3.4, on major platforms the official GCC release is able to pass 100% of the ACATS Ada tests included in the GCC testsuite. In GCC 4.0, more exotic platforms are also able to pass 100% of ACATS.


The compiler is licensed under the terms of the GNU General Public License, with or without a linking exception: The "GNAT GPL Edition" of the runtime is licensed under the GNU General Public License while both the "GNAT Pro Edition" and the FSF's GNAT are under the GNAT Modified General Public License, or, more recently, share the linking exception that is common to all compilers included within the GNU Compiler Collection. All versions leading up to and including 3.15p are licensed under the GMGPL. GNAT-FSF corresponds to the GNAT-GPL version of the previous year (about 9 months apart). At version 4.4, the runtime was relicensed under the GPL version 3 with the GCC Runtime Library Exception.[2] GNAT-FSF is part of most major GNU/Linux or BSD distributions.

The GMGPL license or linking exception in either GNAT Pro runtime or GNAT-FSF runtime permits software that is licensed under a license that is incompatible with the GPL to be linked with the output of Ada standard generic libraries that are supplied with GNAT without breaching the license agreement. Conversely, the GPL license of either GNAT GPL runtime or GNAT GAP runtime requires software that is linked with the standard libraries to be a GPL-compatible license to avoid being in breach of the license agreement.

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