PRESENT — Determine whether an optional dummy argument is specified

Description

Determines whether an optional dummy argument is present.

Syntax

RESULT = PRESENT(A)

Arguments

A May be of any type and may be a pointer, scalar or array value, or a dummy procedure. It shall be the name of an optional dummy argument accessible within the current subroutine or function.

Return value

Returns either TRUE if the optional argument A is present, or FALSE otherwise.

Example



PROGRAM test_present

  WRITE(*,*) f(), f(42)      ! "F T"

CONTAINS

  LOGICAL FUNCTION f(x)

    INTEGER, INTENT(IN), OPTIONAL :: x

    f = PRESENT(x)

  END FUNCTION

END PROGRAM

Standard

Fortran 95 and later

Class

Inquiry function