FORTRAN Reference Manual

Language Elements
FORTRAN Reference Manual—528615-001
2-6
Symbolic Names
Symbolic Names
You use symbolic names to represent the following entities:
•
Main program name
•
Common block name
•
Block data subprogram name
•
Subroutine name
•
External function name
•
Variable name
•
Array name
•
RECORD and RECORD-field name
•
Symbolic constant name
•
Intrinsic function name
•
Statement function name
•
Dummy procedure name
Symbolic names can contain the letters A through Z, the numbers 0 through 9, and the
underscore character (_). References to RECORD fields can also contain the
circumflex character (^).
A symbolic name can be up to 31 characters long. The first character of a symbolic
name must be a letter. The symbolic name can include blanks (in addition to the 31
characters), but the compiler ignores them. The compiler also ignores case. The
compiler treats the following names identically:
MATHROUTINES Math Routines
mathroutines math routines
The following names are valid FORTRAN symbolic names:
a1b4300891
visitors march 1985 with free passes
The following names are invalid:
85 taxes <-- name cannot begin with a digit
amount$ <-- name cannot contain a dollar sign
Context determines whether a particular sequence of characters identifies a keyword
or a symbolic name. No sequence of characters is reserved in all contexts in
FORTRAN.