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From: bangerth@ticam.utexas.edu To: gcc-gnats@gcc.gnu.org Subject: c++/8099: Friend classes and template specializations Date: Mon, 30 Sep 2002 10:16:00 -0000 [thread overview] Message-ID: <20020930170752.5605.qmail@sources.redhat.com> (raw) >Number: 8099 >Category: c++ >Synopsis: Friend classes and template specializations >Confidential: no >Severity: serious >Priority: medium >Responsible: unassigned >State: open >Class: sw-bug >Submitter-Id: net >Arrival-Date: Mon Sep 30 10:16:13 PDT 2002 >Closed-Date: >Last-Modified: >Originator: Wolfgang Bangerth >Release: unknown-1.0 >Organization: >Environment: all gcc versions up to gcc3.2 >Description: [Note that there are already a number of related bug reports, at least c++/8056 comes to my mind, but there may be more.] Maybe this is just some point where the standard is unclear: in 14.5.3.1, the following example is given of a friend declaration: template <typename T> class X { friend class X<int>; }; One would presume that this syntax also holds if a class Y would name a particular (fully specialized) instance of X as a friend. That would be irrespective of whether this instance is derived from the general template for X, or from a partial or full explicit specialization of X. Then the following example should compile (as it does with Compaq's cxx and Intel's icc): -------------------------------- template <int N, typename T> class X; template <typename T> class X<1,T>; template <typename P> class Y { static int i; template <int N, typename T> friend class X; friend class X<1,P>; }; template <typename T> class X<1,T> { X () { Y<T>::i; }; // access private field }; ------------------------------------- gcc rejects the second friend declaration, apparently refering to 14.7.3.17, which states that "An explicit specialization declaration shall not be a friend declaration". So I admit I am confused, both about the standard and the behavior of different compilers. Since gcc behavior restricts the use of the language (IMHO) unduly, I would opt for it to follow the other compiler's interpretation. Regards Wolfgang >How-To-Repeat: >Fix: >Release-Note: >Audit-Trail: >Unformatted:
next reply other threads:[~2002-09-30 17:16 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2002-09-30 10:16 bangerth [this message] 2002-12-16 8:26 Kriang Lerdsuwanakij 2002-12-19 7:33 lerdsuwa
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