Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!bu-cs!purdue!i.cc.purdue.edu!h.cc.purdue.edu!ags
From: ags@h.cc.purdue.edu (Dave Seaman)
Newsgroups: comp.lang.fortran
Subject: Re: i++, i+=1, i=i+1
Message-ID: <3979@h.cc.purdue.edu>
Date: 16 Sep 88 15:21:13 GMT
References: <3976@h.cc.purdue.edu> <3659@lanl.gov>
Reply-To: ags@h.cc.purdue.edu.UUCP (Dave Seaman)
Organization: Purdue University
Lines: 21

In article <3659@lanl.gov> jlg@lanl.gov (Jim Giles) writes:
>No, it doesn't cause the subscript to be evaluated twice.  In Fortran
>functions are not allowed to have side effects.  

May I suggest that you read the standard before making such statements?
At least one variety of side effect is explicitly permitted by the
standard.  I quote the last paragraph of Section 15.5.1, "Function
Subprogram and FUNCTION Statement":

	An external function in a function subprogram may define one or
	more of its dummy arguments to return values in addition to the
	value of the function.

So far I have not found any statements concerning other varieties of side
effects, either for or against.  I do note that section 15.5.3, "Function
Subprogram Restrictions", fails to mention any restrictions on side
effects.

-- 
Dave Seaman	  					
ags@j.cc.purdue.edu