Path: utzoo!utgpu!watmath!clyde!att!rutgers!deimos!uxc!tank!mimsy!chris From: chris@mimsy.UUCP (Chris Torek) Newsgroups: comp.lang.c Subject: Re: side effects in argument lists Message-ID: <14833@mimsy.UUCP> Date: 3 Dec 88 17:39:02 GMT References: <1077@mina.liu.se> <14758@mimsy.UUCP> <2916@arcturus> Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742 Lines: 20 In article <2916@arcturus> evil@arcturus.UUCP (Wade Guthrie) writes: >I believe that binary operators such as '-' are also [dpANS] `sequence points'. No, none of +, -, *, /, or % introduce a sequence point. >Doesn't this cause the behavior of: > > a = b++ - b++; > >to be undefined (different answers depending on right-to-left evaluation >versus left-to-right)? You must be confused about sequence points. The order of evaluation of objects on the left and right sides of the arithmetic operators listed above is undefined. The *only* purpose for a sequence point is to guarantee side effects, so a sequence point within an operation whose evaluation order is undefined would be, er, `pointless'. -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163) Domain: chris@mimsy.umd.edu Path: uunet!mimsy!chris