ENTRY statements can be used to specify additional entry points in external functions and subroutines. ENTRY is a non-executable statement which has the same form as a SUBROUTINE statement. An ENTRY statement may be used at any point in a procedure but all specification statements relating to its dummy arguments must appear in the appropriate place with the other specification statements. If the main entry point is a SUBROUTINE statement than all alternative entry points can be called in the same way as subroutines; if it is a FUNCTION statement than all alternative entry point names can be used as functions. If the main entry point is a character function then all the alternative entry points must also have that type. Alternative entry points may have different lists of dummy arguments; it is up to the user to ensure that all those returning information to the calling program are properly defined before exit.
The rules for the ENTRY statement are necessarily complicated so it is easy to make mistakes. It is generally better, or at least less unsatisfactory, to use a set of separate procedures which share information using common blocks.