Intel(R) Fortran Language Reference (online version)

Program Units and Procedures 8
INTEGER V1, V2
CALL GROUP_SUBS (V1, V2)
See Also
“Defining Explicit Interfaces” for details on interface blocks
Defining Generic Operators
An interface block can be used to define a generic operator. The only procedures allowed in the
interface block are functions that can be referenced as defined operations.
The initial line for such an interface block takes the following form:
INTERFACE OPERATOR (op)
op
Is one of the following:
• A defined unary operator (one argument)
• A defined binary operator (two arguments)
• An extended intrinsic operator (number of arguments must be consistent with the intrinsic
uses of that operator)
The functions within the interface block must have one or two nonoptional arguments with intent
IN, and the function result must not be of type character with assumed length. A defined operation
is treated as a reference to the function.
The following shows the form (and an example) of a defined unary and defined binary operation:
Operation Form Example
Defined unary .defined-operator. operand 1
.MINUS. C
Defined binary operand 2 .defined-operator. operand 3 B .MINUS. C
1. The operand corresponds to the function’s dummy argument.
2. The left operand corresponds to the first dummy argument of the function.
3. The right operand corresponds to the second argument.
For intrinsic operator symbols, the generic properties include the intrinsic operations they
represent. Both forms of each relational operator have the same interpretation, so extending one
form (such as >=) defines both forms ( >= and .GE.).
The following is an example of a procedure interface block defining a new operator:
INTERFACE OPERATOR(.BAR.)
FUNCTION BAR(A_1)
INTEGER, INTENT(IN) :: A_1
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