XL Fortran Enterprise Edition for AIX : User's Guide - IBM

How to Read the Syntax Diagrams and Statements
This document uses notation often referred to as “railroad tracks” to illustrate
syntax for Fortran statements and AIX commands. Syntax for compiler options is
illustrated through statements using notation often referred to as “braces and
brackets”.
Fortran keywords are shown in uppercase: for example, OPEN, COMMON, and
END. You must spell them exactly as they are shown, although they are not
case-sensitive.
Variable names and user-specified names appear in lowercase italics; for example,
array_element_name.
If a variable or user-specified name ends in _list, it means that you can provide a
list of terms that are separated by commas.
You must enter punctuation marks, parentheses, arithmetic operators, and other
special characters as part of the syntax.
Syntax Diagrams
v Read syntax diagrams from left to right and from top to bottom, following the
path of the line:
– The ►►─── symbol indicates the beginning of a command.
– The ───► symbol indicates that the command syntax continues on the next
line.
– The ►─── symbol indicates that a command is continued from the previous
line.
– The ───►◄ symbol indicates the end of a command.
– Diagrams of syntactical units smaller than complete statements start with the
►─── symbol and end with the ───► symbol.
– Constructs, interface blocks and derived type definitions consist of several
individual statements. For such items, individual syntax diagrams show the
required order for the equivalent Fortran statements.
v Required items appear on the main path (the main path):
►► command_name required_argument ►◄
v
Optional items appear below the main path:
►►
command_name
optional_argument
►◄
v
If you can choose from two or more items, they appear vertically, in a stack.
If you must choose one of the items, one item of the stack appears on the main
path:
►► command_name required_argument
required_argument
►◄
If choosing one of the items is optional, the entire stack appears below the main
path:
2 XL Fortran Enterprise Edition for AIX : User’s Guide