.. _what-is-gnu-modula-2:

What is GNU Modula-2
********************

GNU Modula-2 is a `front end <http://gcc.gnu.org/frontends.html>`_
for the GNU Compiler Collection (`GCC <http://gcc.gnu.org/>`_).
The GNU Modula-2 compiler is compliant with the PIM2, PIM3, PIM4 and
ISO dialects.  Also implemented are a complete set of free ISO
libraries and PIM libraries.

The four Modula-2 dialects supported are defined in the following
references:

PIM2: 'Programming in Modula-2', 2nd Edition, Springer Verlag, 1982,
1983 by Niklaus Wirth (PIM2).

PIM3: 'Programming in Modula-2', 3rd Corrected Edition, Springer Verlag,
1985 (PIM3).

PIM4: 'Programming in Modula-2', 4th Edition, Springer Verlag, 1988
(`PIM4 <http://freepages.modula2.org/report4/modula-2.html>`_).

ISO: the ISO Modula-2 language as defined in 'ISO/IEC Information
technology - programming languages - part 1: Modula-2 Language,
ISO/IEC 10514-1 (1996)'