Language standards

This section briefly summarizes the XL Fortran language standard implementations it follows. The Qualifying elements section contains details on how XL Fortran marks language standard specific information.

Fortran 2003 Standard

Segments of this document contain information based on the Fortran 2003 Standard. The standard is open to continual interpretation, modification and revision. IBM reserves the right to modify the behavior of any features of this product to conform with future interpretations of this standard.

Fortran 95

The Fortran 95 language standard is upward-compatible with the FORTRAN 77 and Fortran 90 language standards, excluding deleted features. Some of the improvements provided by the Fortran 95 standard are:

The Fortran standard committees respond to questions of interpretation about aspects of Fortran. Some questions can relate to language features already implemented in the XL Fortran compiler. Any answers given by these committees relating to these language features can result in changes to future releases of the XL Fortran compiler, even if these changes result in incompatibilities with previous releases of the product.

Fortran 90

Fortran 90 offers many new features and feature enhancements to FORTRAN 77. The following topics outline some of the key features that Fortran 90 brings to the FORTRAN 77 language:

IBM Extensions

An IBM extension generally modifies a rule or restriction from a given standards implementation. In this document, IBM extensions to the Fortran 2003, Fortran 90, and Fortran 95 standards are marked as indicated in Qualifying elements section.

Other standards and standards documents

OpenMP API Version 2.5

The OpenMP API provides additional features which you can use to supplement the existing FORTRAN 77, Fortran 90 and Fortran 95 language standards.

The OpenMP Architecture Review Board (ARB) responds to questions of interpretation about aspects of the API. Some of these questions can relate to interface features implemented in this version of the XL Fortran compiler. Any answers given by this committee relating to the interface can result in changes in future releases of the XL Fortran compiler, even if these changes result in incompatibilities with previous releases of the product.

You can find information pertaining to the implementation of OpenMP API Version 2.5 in the following sections:

Standards documents

XL Fortran is designed according to the standards listed in the Standards documents section. You can refer to these standards for precise definitions of some of the features found in this document.