Intel Fortran Language Reference - NCI National Facility

8 Intel Fortran Language Reference
A procedure must not have more than one explicit interface in a given scoping unit.
A interface block containing generic-spec specifies a generic interface for the following
procedures:
• The procedures within the interface block
Any generic name, defined operator, or equals symbol that appears is a generic identifier for
all the procedures in the interface block. For the rules on how any two procedures with the
same generic identifier must differ, see “Unambiguous Generic Procedure References”.
• The module procedures listed in the MODULE PROCEDURE statement
The module procedures must be accessible by a USE statement.
To make an interface block available to multiple program units (through a USE statement), place
the interface block in a module.
The following rules apply to interface blocks containing pure procedures:
• The interface specification of a pure procedure must declare the INTENT of all dummy
arguments except pointer and procedure arguments.
• A procedure that is declared pure in its definition can also be declared pure in an interface
block. However, if it is not declared pure in its definition, it must not be declared pure in an
interface block.
Examples
The following example shows a simple procedure interface block with no generic specification:
SUBROUTINE SUB_B (B, FB)
REAL B
...
INTERFACE
FUNCTION FB (GN)
REAL FB, GN
END FUNCTION
END INTERFACE
See Also
• “Functions”
• “Subroutines”
• “Use and Host Association”
• “Modules and Module Procedures”
• “Pure Procedures”
• “Determining When Procedures Require Explicit Interfaces”
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