From 6074741618169098078 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,954370b2ad698b43 X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 1993-10-12 16:19:58 PST Newsgroups: comp.std.c++ Path: gmd.de!xlink.net!howland.reston.ans.net!pipex!uunet!titan!lpi!pkt From: pkt@lpi.liant.com (Scott Turner) Subject: Re: refcast ambiguity "(( &) )" Message-ID: <1993Oct12.162854.1915@lpi.liant.com> Sender: pkt@lpi (Scott Turner) Organization: Liant Software Corporation References: <1993Oct6.211357.7098@objy.com> Date: Tue, 12 Oct 1993 16:28:54 GMT Lines: 27 In article <1993Oct6.211357.7098@objy.com>, jacob@objy.com (Jacob Butcher) writes: > most compilers (for example, Sun's) compile these two statements identically: > > to &t = f; > to &t = ((to &) (f)); > > However, IBM's xlC compiler for AIX on an IBM RT compiles them differently. > However, their implementation > violates what I (perhaps naively) assume to be an invariant of the language, > which is that if it is legal to assign an expression of type F to a variable > of type T, then it is legal to *cast* an expression of type F to type T, and > the operations are identical. That would be nice as an invariant, but C++ explicit casts break it. For example, void foo(float x) { const int &r1 = x; // Refer to a temporary int object. const int &r2 = (const int &)x; // Reinterpret the bits of x. } -- Prescott K. Turner, Jr. Liant Software Corp. (developers of LPI languages) 959 Concord St., Framingham, MA 01701 USA (508) 872-8700 UUCP: uunet!lpi!pkt Internet: pkt@lpi.liant.com