From -1578120885038685746 X-Google-Thread: f78e5,6bb94f62f97d8704,start X-Google-NewGroupId: yes X-Google-Attributes: gid7894ca11fe,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news1.google.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!news.giganews.com.POSTED!not-for-mail NNTP-Posting-Date: Fri, 16 Jul 2010 16:20:08 -0500 Return-Path: To: (Usenet) From: "Johannes Schaub (litb)" Newsgroups: comp.std.c++ Subject: A couple of questions on new-expression with array initializer Followup-To: comp.std.c++ Organization: T-Online Sender: cppmods@cs.rpi.edu Approved: james.dennett@gmail.com Message-ID: Content-Type: text/plain; charset="ISO-8859-1" X-Original-Date: Thu, 15 Jul 2010 23:52:11 +0200 X-Submission-Address: std-c++@netlab.cs.rpi.edu Date: Fri, 16 Jul 2010 16:19:00 CST Lines: 44 X-Usenet-Provider: http://www.giganews.com X-Trace: sv3-LrMmvK6lBTEC6hJPu7koObs4co75tyX5a8p7I3Dw0Imq8X4LTV6VdxrsKzdgUvEqaW8P+u/V9mglltW!OgHQG584/vMqMI4qGHiMHyoxy1Hu122yT/4yV/GqIu0ag2Ss4UrHvEyEa7qF X-Complaints-To: abuse@giganews.com X-DMCA-Notifications: http://www.giganews.com/info/dmca.html X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 Xref: g2news1.google.com comp.std.c++:2772 Q1: The FCD says that the following code is ill-formed. But we can't know that until runtime int n = 2; new int[n]{1, 2, 3}; How is the runtime supposed to emit the diagnostic message? See 8.5.1/6 and 5.3.4/15: 6 An initializer-list is ill-formed if the number of initializer-clauses exceeds the number of members or elements to initialize. Hmm, GCC just segfaults. I wonder whether printing "segfault" is a valid runtime diagnostic message. Any insights? Q2: Is the following valid? new (int[]){1, 2, 3} I know that without the parens, it's syntactically invalid. But with the parens, "int[]" it's a type-id and valid, but it says at 5.3.4/1: "The new-expression attempts to create an object of the type-id (8.1) or new-type-id to which it is applied. The type of that object is the allocated type. This type shall be a complete object type, ..." At first sight it seems to forbid it, because the type-id specifies an incomplete type. But the constraint is done upon the object-type. And that type is, after gone through 8.5.1, "int[3]". GCC forbids it and says "error: invalid use of array with unspecified bounds". Is GCC right? Is there any clear wording about it? Thanks for any insight. -- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@netlab.cs.rpi.edu] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.comeaucomputing.com/csc/faq.html ]