5. Procedures

5.1 Definitions

Procedures (or sub-programs, depending on the language, in Ada for example) are defined in the Programming languages article. Introduction . They help to break down an application into smaller, more easily understandable units, thereby increasing its maintainability.

A procedure is comparable to a main program, both in terms of execution logic and syntax structure. The major difference is that a program is launched by an operating system command, whereas a procedure is executed by a call from a Fortran instruction.

There are two syntactic categories of procedures in Fortran:

• subprograms (SUBROUTINE), which define an action and are called by a CALL instruction...