Intel® Fortran Compiler Classic and Intel® Fortran Compiler Developer Guide and Reference

ID 767251
Date 11/07/2023
Public

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Document Table of Contents

ENTRY

Statement: Provides one or more entry points within a subprogram. It is not executable and must precede any CONTAINS statement (if any) within the subprogram.

ENTRY name[ ( [d-arg[,d-arg]...] ) [RESULT (r-name)] ]

name

Is the name of an entry point. If RESULT is specified, this entry name must not appear in any specification statement in the scoping unit of the function subprogram.

d-arg

(Optional) Is a dummy argument. The dummy argument can be an alternate return indicator (*) if the ENTRY statement is within a subroutine subprogram.

r-name

(Optional) Is the name of a function result. This name must not be the same as the name of the entry point, or the name of any other function or function result. This parameter can only be specified for function subprograms.

Description

ENTRY statements can only appear in external procedures or module procedures.

An ENTRY statement must not appear in an executable construct.

When the ENTRY statement appears in a subroutine subprogram, it is referenced by a CALL statement. When the ENTRY statement appears in a function subprogram, it is referenced by a function reference.

An entry name within a function subprogram can appear in a type declaration statement.

Within the subprogram containing the ENTRY statement, the entry name must not appear as a dummy argument in the FUNCTION or SUBROUTINE statement, and it must not appear in an EXTERNAL or INTRINSIC statement. For example, neither of the following are valid:

(1)  SUBROUTINE SUB(E)
     ENTRY E
     ...

(2)  SUBROUTINE SUB
     EXTERNAL E
     ENTRY E
     ...

The procedure defined by an ENTRY statement can reference itself if the function or subroutine was defined as RECURSIVE.

Dummy arguments can be used in ENTRY statements even if they differ in order, number, type and kind parameters, and name from the dummy arguments used in the FUNCTION, SUBROUTINE, and other ENTRY statements in the same subprogram. However, each reference to a function, subroutine, or entry must use an actual argument list that agrees in order, number, and type with the dummy argument list in the corresponding FUNCTION, SUBROUTINE, or ENTRY statement.

Dummy arguments can be referred to only in executable statements that follow the first SUBROUTINE, FUNCTION, or ENTRY statement in which the dummy argument is specified. If a dummy argument is not currently associated with an actual argument, the dummy argument is undefined and cannot be referenced. Arguments do not retain their association from one reference of a subprogram to another.

Example

C  This fragment writes a message indicating
C  whether num is positive or negative
   IF (num .GE. 0) THEN
     CALL Sign
   ELSE
     CALL Negative
   END IF
   ...
   END
SUBROUTINE Sign
   WRITE (*, *) 'It''s positive.'
   RETURN
   ENTRY Negative
   WRITE (*, *) 'It''s negative.'
   RETURN
END SUBROUTINE