ISO/IEC JTC1/SC22/WG5 N1494 Committee Draft revision of ISO/IEC 1539-1:1997 - Programming Language Fortran - Part 1: Base language Abstract Fortran is a computer language for scientific and technical programming that is tailored for efficient run-time execution on a wide variety of processors. It was first standardized in 1966 and the standard has since been revised three times (1978, 1991, 1997). The revision of 1991 was major and those of 1978 and 1997 were relatively minor. This proposed fourth revision is major and has been made following a meeting of ISO/IEC JTC1/SC22/WG5 in 1997 that considered all the requirements of users, as expressed through their national bodies. The significant enhancements in the 1991 revision were dynamic storage, structures, derived types, pointers, type parameterization, modules, and array language. The main thrust of the 1997 revision was in connection with alignment with HPF (High Performance Fortran). The major enhancements for this revision are (1) Derived type enhancements: parameterized derived types, improved control of accessibility, improved structure constructors, and finalizers. (2) Object oriented programming support: type extension and inheritance, polymorphism, dynamic type allocation, and type-bound procedures. (3) Data manipulation enhancements: allocatable components, deferred type parameters, VOLATILE attribute, explicit type specification in array constructors, pointer enhancements, extended initialization expressions, and enhanced intrinsic procedures. (4) Input/output enhancements: asynchronous transfer, stream access, user specified transfer operations for derived types, user specified control of rounding during format conversions, named constants for preconnected units, the flush statement, regularization of keywords, and access to error messages. (5) Procedure pointers. (6) Support for IEC 60559 (IEEE 754) exceptions. (7) Interoperability with the C programming language. (8) Support for international usage: access to ISO 10646 4-byte characters and choice of decimal or comma in numeric formatted input/output. (9) Enhanced integration with the host operating system: access to command line arguments, environment variables, and processor error messages. In addition, there are numerous minor enhancements. Except in extremely minor ways, this revision is upwards compatible with the current standard, that is, a program that conforms to the present standard will conform to the revised standard. The enhancements are in response to demands from users and will keep Fortran appropriate for the needs of present-day programmers without losing the vast investment in existing programs.