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From: "sstrasser at systemhaus-gruppe dot de" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/19809] New: Multiple definitions of friend functions in template classes Date: Mon, 07 Feb 2005 23:36:00 -0000 [thread overview] Message-ID: <20050207181328.19809.sstrasser@systemhaus-gruppe.de> (raw) This report is based on <16899453.0502060835.6c893401@posting.google.com> given this testcase: #include <iostream> template<int i> struct n{ friend void foo(){ std::cerr << i << std::endl;; } }; int main(){ n<1> n1; n<2> n2; n<3> n3; foo(); } there must be a bug here, though I'm not sure what exactly it is. a) it could be a multiple definition of foo, which is reported by version 3.3.4, but not by 4.0.0 and 3.4.3. b) std note 14.5.3.3 could mean that it's not a multiple definition: <<<3 When a function is defined in a friend function declaration in a class template, the function is defined when the class template is first instantiated. The function is defined even if it is never used.>>> so if it's _only_ defined on the first instantiation this is not a multiple definition - but then I don't think it is legal to use the template arguments of struct n in the function definition c) even if b) is wrong and usage of template arguments is allowed, there's still a bug, because the result of the testcase above is "3", so the _last_ instantiation is used. comeau C++ chooses a), so does 3.3.4. -- Summary: Multiple definitions of friend functions in template classes Product: gcc Version: 4.0.0 Status: UNCONFIRMED Severity: normal Priority: P2 Component: c++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: sstrasser at systemhaus-gruppe dot de CC: gcc-bugs at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19809
next reply other threads:[~2005-02-07 18:14 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2005-02-07 23:36 sstrasser at systemhaus-gruppe dot de [this message] 2005-02-08 3:37 ` [Bug c++/19809] [3.4/4.0 Regression] " giovannibajo at libero dot it 2005-02-16 19:12 ` pinskia at gcc dot gnu dot org 2005-05-19 17:53 ` [Bug c++/19809] [3.4/4.0/4.1 " mmitchel at gcc dot gnu dot org 2005-07-22 21:18 ` pinskia at gcc dot gnu dot org 2005-09-27 16:25 ` mmitchel at gcc dot gnu dot org
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