1. About This Guide

For ease of exposition, ‘GNAT Pro’ will be referred to simply as ‘GNAT’ in the remainder of this document.

This guide describes the use of GNAT, a compiler and software development toolset for the full Ada programming language. It documents the features of the compiler and tools, and explains how to use them to build Ada applications.

GNAT implements Ada 95, Ada 2005 and Ada 2012, and it may also be invoked in Ada 83 compatibility mode. By default, GNAT assumes Ada 2012, but you can override with a compiler switch (Compiling Different Versions of Ada) to explicitly specify the language version. Throughout this manual, references to ‘Ada’ without a year suffix apply to all Ada 95/2005/2012 versions of the language.

1.1. What This Guide Contains

This guide contains the following chapters:

Appendices cover several additional topics:

1.2. What You Should Know before Reading This Guide

This guide assumes a basic familiarity with the Ada 95 language, as described in the International Standard ANSI/ISO/IEC-8652:1995, January 1995. It does not require knowledge of the features introduced by Ada 2005 or Ada 2012. Reference manuals for Ada 95, Ada 2005, and Ada 2012 are included in the GNAT documentation package.

1.4. A Note to Readers of Previous Versions of the Manual

In early 2015 the GNAT manuals were transitioned to the reStructuredText (rst) / Sphinx documentation generator technology. During that process the GNAT User’s Guide was reorganized so that related topics would be described together in the same chapter or appendix. Here’s a summary of the major changes realized in the new document structure.

1.5. Conventions

Following are examples of the typographical and graphic conventions used in this guide:

  • Functions, utility program names, standard names, and classes.

  • Option flags

  • File names

  • Variables

  • Emphasis

  • [optional information or parameters]

  • Examples are described by text

    and then shown this way.
  • Commands that are entered by the user are shown as preceded by a prompt string comprising the $ character followed by a space.

  • Full file names are shown with the ‘/’ character as the directory separator; e.g., parent-dir/subdir/myfile.adb. If you are using GNAT on a Windows platform, please note that the ‘\’ character should be used instead.