HP Fortran Programmer's Reference (September 2007)

HP Fortran statements
IMPLICIT
Chapter 10 371
IMPLICIT
Changes or voids default typing rules.
Syntax
The IMPLICIT statement can take either of the following forms:
• First form:
IMPLICIT type ( range-list )[, type ( range-list ) ,]...
• Second form:
IMPLICIT NONE
type is the data type to be associated with the corresponding letters in
range-list .
range-list is a comma-separated list of letters or ranges of letters (for example, A-Z or
I-N) to be associated with type . Writing a range of letters has the same
effect as writing a list of single letters.
Description
The IMPLICIT statement can be used either to change or void the default typing rules within
the program unit in which it appears, depending on which of the two forms the statement
takes.
First form
This form of the IMPLICIT statement specifies type as the data type for all variables, arrays,
named constants, function subprograms, ENTRY names in function subprograms, and
statement functions that begin with any letter in range-list and that are not explicitly
given a type.
Within the specification statements of a program unit, IMPLICIT statements must precede all
other specification statements, except possibly the DATA and PARAMETER statements.
The same letter must not appear as a single letter or be included in a range of letters, more
than once in all of the IMPLICIT statements in a scoping unit.
For information on how the IMPLICIT and PARAMETER statements interact, refer to
“PARAMETER (statement and attribute)” on page 420.
Second form