INTRINSIC (statement and attribute)

Identifies an intrinsic procedure.

Syntax

The syntax of the type declaration statement with the INTRINSIC attribute is:

type , attrib-list :: intrinsic-function-name-list

The syntax of the INTRINSIC statement is:

INTRINSIC intrinsic-procedure-name-list

where intrinsic-procedure-name-list is a comma-separated list of procedure names.

Note that, like the EXTERNAL statement, the INTRINSIC statement does not have optional colons.

Description

The INTRINSIC statement and attribute identifies a specific or generic name as that of an intrinsic procedure, enabling it to be used as an actual argument. (Only a specific function name—or a generic name that is the same as the specific name—can be used as an actual argument; see “Procedure dummy argument”.) The INTRINSIC statement is necessary to inform the compiler that a name is intrinsic and is not the name of a variable. Whenever an intrinsic name is passed as an actual argument and no other appearance of the name in the same scoping unit indicates that it is a procedure, it must be specified by the calling program in an INTRINSIC statement, or (if a function name) in a type declaration statement that includes the INTRINSIC attribute.

Each name can appear only once in an INTRINSIC statement and in at most one INTRINSIC statement within the same scoping unit. Also, a name cannot appear in both an EXTERNAL and an INTRINSIC statement within the same scoping unit.

Examples

SUBROUTINE subr  ! caller
  DOUBLE PRECISION :: dsin,x,y,func
  INTRINSIC dsin
  ...
  y = func(dsin,x)
  ...
END SUBROUTINE subr
 
DOUBLE PRECISION FUNCTION func(proc,y)  ! callee
  DOUBLE PRECISION :: y, proc
  ...
  func = proc(y)
  ...
END FUNCTION func

Related statements

EXTERNAL

Related concepts

For additional information about passing user-defined and intrinsic procedures as arguments, see “Procedure dummy argument”. Intrinsic procedures are described in “Intrinsic procedure specifications”.