Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!lamaster From: lamaster@ames.arc.nasa.gov (Hugh LaMaster) Newsgroups: comp.lang.fortran Subject: Re: Side Effects of FORTRAN Functions Message-ID: <15436@ames.arc.nasa.gov> Date: 24 Sep 88 17:55:23 GMT References: <50500076@uxe.cso.uiuc.edu> Reply-To: lamaster@ames.arc.nasa.gov.UUCP (Hugh LaMaster) Organization: NASA Ames Research Center, Moffett Field, Calif. Lines: 27 In article <50500076@uxe.cso.uiuc.edu> hirchert@uxe.cso.uiuc.edu writes: : >Misinformation and misinterpretations on the subject of side effects in FORTRAN >abound. I will attempt to throw some light on the subject. Let me point out : > a standard-conforming FORTRAN program may include functions which have side > effects, but the program is prohibited from referencing the results of those > side effects. > > > > The random number generator is the usual example of something that produces different results depending on which call it is. If I understand the description properly, it is now prohibited to implement a random number generator as a function: it should be a subroutine. Is this correct? (I don't have a problem with it- other than all those old codes which use x=ranf(i) :-) ). -- Hugh LaMaster, m/s 233-9, UUCP ames!lamaster NASA Ames Research Center ARPA lamaster@ames.arc.nasa.gov Moffett Field, CA 94035 Phone: (415)694-6117