1. About This Guide#

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, Ada 2012, and Ada 202x, 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 versions of the language, starting with Ada 95.

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. Reference manuals for Ada 95, Ada 2005, and Ada 2012 are included in the GNAT documentation package.

1.4. 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.