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Functions
And
Subroutines
5-10
NOTE
The subscript value remains constant as long as the arguments are
associated, even
if
the subscript contains variables redefined during the
association.
Argument association can be carried
through
more
than
one level
of
procedure
reference. A valid association exists at the last level, however, only if the association
is
maintained
through
all intermediate levels. The association normally terminates
when a
RETURN
or
END
is
executed. The association
is
not retained from one pro-
cedure reference
to
the next.
5.3.3.1 Agreement
Of
Argument Lengths
If
a
dummy
argument
is
type character, its actual argument must be the same type
and
length.
If
the
dummy
is
an
array name, the length requirement applies
to
each
element in the array.
If
the dllmmy
argumentis
type integer. the arguments must again
agreeiu
type
and
lepgth~lfaninteger
c()nstant
is
used as
an
actual
argument, its length is deterInined
as
shq""n
in~ection
2.2.Z.2.That
is,
an
integer
without
abas~suffix
has the default
integer
variable
length;if
the base
of
the integer
constantisstated
explicitly, tbe pro-
c~ssordetermines
its length implicitly.
5.3.3.2 Variables As Dummy Arguments
A variable
dummy
argument can be associated with an actual variable, array ele-
ment,
or
expression.
If
the actual
argument
is
a variable name
or
array
element
name, its
dummy
argument can be defined
or
redefined within the subprogram.
Otherwise, if the actual argument
is
a
constant,
function reference,
or
expression, its
dummy
argument
must
not be redefined within the subprogram.
5.3.3.3 Arrays As Dummy Arguments
An array
dummy
argument
can be associated with an actual
array
name
or
array ele-
ment name. The
number
and
size
of
dimensions in an actual
argument
array
declarator can be
differept from the dimensions in its associated
dummy
array
declarator.
If
the actual argument
is
an array name, the size
of
the
dummy
argument array must
not
be greater
than
the size
of
the actual argument array.
If
the actual argument
is
an array element name with a subscript
'p,'
the
dummy
ar-
ray element with a subscript
'q'
becomes associated with the actual array element
with the subscript value (p
+
q-l).
The size
of
the
dummy
array
must not be greater
than
the size
of
the actual array plus one minus the subscript value
of
the array ele-
ment.
5.3.3.4 Procedures As Dummy Arguments
I f a
dummy
argument
is
used as if it were an external function, the associated actual
argument
must be an intrinsic function, external function,
or
dummy
procedure.
If
a
dummy
argument appears in a type statement
and
an
EXTERNAL
statement, the
actual
argument
must be the
name
of
a function
or
dummy procedure.
If
the
dummy
argument
is
referenced as a subroutine, the actual argument must be the
name
of
a
subroutine
or
dummy procedure
and
must
not
appear
in a type statement
or
be
referenced as a function.
FORTRAN-80