From -4046583691309537523 X-Google-Thread: 7894ca11fe,98decb90a5fd464a,start X-Google-Attributes: gid7894ca11fe,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news2.google.com!news2.google.com!newsfeed.stanford.edu!news.kjsl.com!news.alt.net!frodo.cs.rpi.edu!not-for-mail From: Scott Meyers Newsgroups: comp.std.c++ Subject: Inconsistencies in unique_ptr and shared_ptr APIs Date: Sun, 7 Jun 2009 20:16:49 CST Organization: unknown Lines: 30 Sender: cppmods@cs.rpi.edu Approved: stephen.clamage@sun.com Message-ID: NNTP-Posting-Host: netlab.cs.rpi.edu Content-Type: text/plain; charset=ISO-8859-1; format=flowed To: (Usenet) Return-Path: X-Original-Date: Sat, 06 Jun 2009 15:55:06 -0700 X-Submission-Address: std-c++@netlab.cs.rpi.edu Xref: g2news2.google.com comp.std.c++:823 In September 2005, Joe Gottman posted to this group about inconsistencies in the interfaces for unique_ptr and shared_ptr that bore no apparent relationship to their fundamental functionality ( http://tinyurl.com/nmjwuu ). He noted that: - "Shared_ptr has only operator ==, operator !=, and operator <. Unique_ptr has these three plus operator >, operator <=, and operator>=." - Only unique_ptr has special support for arrays. - Only shared_ptr supports const_pointer_cast, static_pointer_cast, and dynamic_ptr_cast. These discrepancies are also present in the current C++0x draft (N2857), so presumably there is a reason for them. Can somebody please explain what is is? I'd also be interested to know why the type of the deleter is part of the type of a unique_ptr but is not part of the type of a shared_ptr. Finally, I'd like to know why unique_ptr gets its own subsection in the standard (20.8.12) rather than being under "Smart pointers" (20.8.13) with shared_ptr and weak_ptr. (Heck, weak_ptr isn't even really a pointer, because it doesn't overload operator->.) Thanks for all enlightenment. Scott -- [ 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 ]