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NAG Fortran Compiler Description

The NAG Fortran Compiler is a full ISO standard implementation of the Fortran 95 language with the addition of almost all of ISO Fortran 2003. It's development is based on the NAGWare f90 Compiler which was launched in June 1991 and was the world's first Fortran 90 compiler. Like its predecessor, the NAG Fortran Compiler has been thoroughly tested and widely used since its launch in 1997.

Many common extensions to Fortran 77 are allowed to provide support for legacy code. For example, the Fortran Compiler allows processing of code containing tab format input, byte-sized declarations (e.g INTEGER*2) and DOUBLE COMPLEX.

The vast majority of Fortran 2003 has been implemented in Release 5.2, but the following language elements have not yet been added to the Compiler.

1. Ad hoc type comparison
2. Parameterised derived types
3. Finalisation
4. Defined I/O
5. Structure constructor syntax enhancements

• Summary of the new Fortran 2003 language capabilities

The NAG Fortran Compiler includes processing capabilities for HPF source code, though only single processor output is generated, and there is a complete HPF support library.

To achieve portability, The NAG Fortran Compiler uses C as its intermediate language - automatically invoking the host compiler to produce object code.

Extensive error messages are given by the Compiler, both those required by the ISO standard and additional compile and run-time information. The messages are informative rather than cryptic and usually contain context information to assist in identifying and rectifying problems. For this reason the Compiler is particularly suited to teaching and for programmers wishing to update their skills to the new language. Programmers who wish to produce portable, standard-conforming code will benefit from the analysis carried out by the Compiler

The NAG Fortran Compiler features many optional run-time checks, including - array bounds, pointer association, pointer references, procedure references, dangling pointers and undefined variables. There are also facilities to trace memory allocation and deallocation and help to identify memory leaks.

Built-in modules provide an interface to a large number of Posix system calls, e.g. GETARG, SYSTEM, and many others.

Automatic garbage collection is available as an option. This prevents memory leaks by deallocating memory that can no longer be accessed by the program.

A maintenance service is available for the compiler giving access to bug fixes and new releases.

Availability

If your machine and operating system combination are included in the current list of implementations then the only additional requirement is that you have a C compiler available. In general this will be the manufacturer's default C compiler for the target machine, but on some platforms support there is an implementation for an alternative C compiler, e.g. GCC.

If you require any further information on availability then please call us to advise us of your requirements.