220 19446 <1544148.KS9yEPmrxK@tjmaciei-mobl4> article Path: news.gmane.org!not-for-mail From: Thiago Macieira Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Testing for supported features: Per-feature macros? Sentinel compilation? 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[78.47.120.188]) by mx.google.com with ESMTP id sd17si2678407wjb.102.2015.07.30.09.02.56 for ; Thu, 30 Jul 2015 09:02:56 -0700 (PDT) Received-SPF: pass (google.com: domain of thiago@macieira.org designates 78.47.120.188 as permitted sender) client-ip=78.47.120.188; Original-Received: from tjmaciei-mobl4.localnet (unknown [IPv6:2601:1c0:5803:81c9:c03f:789a:87c5:1fb5]) by gondolin.macieira.info (Postfix) with ESMTPSA id DE5CB11B694 for ; Thu, 30 Jul 2015 09:02:53 -0700 (PDT) User-Agent: KMail/4.14.9 (Linux/4.1.2-1-desktop; KDE/4.14.9; x86_64; ; ) In-Reply-To: X-Original-Sender: thiago@macieira.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of thiago@macieira.org designates 78.47.120.188 as permitted sender) smtp.mail=thiago@macieira.org Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:19446 Archived-At: On Thursday 30 July 2015 11:14:21 Matthew Woehlke wrote: > Hmm... that said, you might be right in the sense that IIRC there are > "PP" directives that are left in place (e.g. #pragma), or even added > (e.g. #line). So maybe my previous comment doesn't apply. Disregard, > then :-). The problem with that is that the compiler now sees the invalid code too and needs to decide what (not) to do with it. You can't use the preprocessor to remove code the compiler shouldn't see. > On 2015-07-29 20:55, Thiago Macieira wrote: > > How often do you compile the library with VS 2010 (which supports move > > semantics) and then compile the application with VS 2005? Answer: never. > > You could be using a pre-built library that was built with a newer > compiler to build an application on a machine that has only an older > compiler. (Although, pre-built stuff tends to use the oldest compiler > possible, or be available built with multiple compiler versions.) You cannot do that. Let's forget the fact that MSVC versions are incompatible with each other altogether and analyse the more common case of Unix shared libraries: The rule of thumb on shared libraries on Unix systems is that you must run with a version equal to or higher than the one you linked to. Breaking that rule is not supported by anyone. > It *can* happen, but the library headers may well check for that and > raise an error. What headers? The problem is linking and dynamic linking. -- Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org Software Architect - Intel Open Source Technology Center PGP/GPG: 0x6EF45358; fingerprint: E067 918B B660 DBD1 105C 966C 33F5 F005 6EF4 5358 -- --- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. 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