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From: mrc@Tomobiki-Cho.CAC.Washington.EDU (Mark Crispin)
Newsgroups: comp.edu,uw.general
Subject: Re: Recursion Summary
Message-ID: <10143@milton.u.washington.edu>
Date: 29 Oct 90 04:52:36 GMT
References: <1990Oct23.211651.10227@contact.uucp> <9868@milton.u.washington.edu> <9882@milton.u.washington.edu> <1990Oct25.160014.17216@watdragon.waterloo.edu>
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In article <1990Oct25.160014.17216@watdragon.waterloo.edu> bpdickson@rose.uwaterloo.ca (Brian Dickson) writes:
>>Recursion is nothing more a reentrant subroutine call.
>Error #1: reentrant subroutine call == recursion
>Example: inexperienced FORTRAN programmer writes recursive program,
>	wonders why weird things happen. (I observed this one.) :-(

Fortran subroutines are non-reentrant, although there is no error
check for subroutine call reentrancy.

Some Fortran compilers generate subroutine calls using a JSR-type
machine instruction that stores the return PC in a static location
(e.g. the first location of the subroutine) and return by an
indirect-jump on that static location.

Other compilers may use a stack subroutine-call instruction, leading
to a false notion that Fortran has "reentrancy".

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