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From: Gianni Mariani <gianni@mariani.ws> To: nobody@gcc.gnu.org Cc: gcc-prs@gcc.gnu.org, Subject: Re: c++/10541: Is NULL a valid pointer-type template argument? Date: Tue, 29 Apr 2003 17:56:00 -0000 [thread overview] Message-ID: <20030429175600.23548.qmail@sources.redhat.com> (raw) The following reply was made to PR c++/10541; it has been noted by GNATS. From: Gianni Mariani <gianni@mariani.ws> To: Wolfgang Bangerth <bangerth@ices.utexas.edu> Cc: gcc-bugs@gcc.gnu.org, gcc-gnats@gcc.gnu.org Subject: Re: c++/10541: Is NULL a valid pointer-type template argument? Date: Tue, 29 Apr 2003 10:47:58 -0700 Wolfgang Bangerth wrote: >>I remember reading a while back that C/C++ considers the value 0 to be a >>valid value for any pointer type. Hence 0 CAN BE of type char *. >> >> > >Well, 0 is of type "signed int". It can be converted to any pointer type >implicitly. The question is whether the compiler is supposed to do >implicit conversions for template args. I don't think so. > > > >>Other compilers seem to take this value. >> >> > >icc doesn't, for example. > > In this posting: news://nntp.concentric.net:119/vatbv4b1hbd6d3@corp.supernews.com http://groups.google.com/groups?dq=&hl=en&lr=&ie=UTF-8&threadm=b8m2ve%243h4%40dispatch.concentric.net&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DUTF-8%26group%3Dcomp.lang.c%252B%252B >According to 14.3.2/1 a pointer template argument must be a pointer to >> an object with external linkage. 0 is certainly not such a pointer. >> >> Generally, you'll need >> >> IType<char*, someexternarrayname> >> or >> IType<char*, &someexternchar> >> >> Apparently, Comeau gets this wrong, allowing IType<char *, >> static_cast<char *>(0)>. > > There is an open issue 354 on this, BTW. I would think that Comeau is just running ahead of the pack (along with EDG, MS, Borland, and Cfront -- as described in the issue). Gcc and Sun are the pack. Seems like this is an open issue.
next reply other threads:[~2003-04-29 17:56 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2003-04-29 17:56 Gianni Mariani [this message] -- strict thread matches above, loose matches on Subject: below -- 2003-04-29 17:26 Wolfgang Bangerth 2003-04-29 17:26 Wolfgang Bangerth 2003-04-29 17:26 Gianni Mariani 2003-04-29 17:16 Martin Sebor 2003-04-29 16:37 bangerth
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