From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from localhost (localhost [127.0.0.1]) by olra.theworths.org (Postfix) with ESMTP id 69082431FAF for ; Tue, 8 May 2012 13:13:35 -0700 (PDT) X-Virus-Scanned: Debian amavisd-new at olra.theworths.org X-Spam-Flag: NO X-Spam-Score: 0 X-Spam-Level: X-Spam-Status: No, score=0 tagged_above=-999 required=5 tests=[none] autolearn=disabled Received: from olra.theworths.org ([127.0.0.1]) by localhost (olra.theworths.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id S1fK85hwqvwY for ; Tue, 8 May 2012 13:13:34 -0700 (PDT) Received: from guru.guru-group.fi (guru-group.fi [87.108.86.66]) by olra.theworths.org (Postfix) with ESMTP id EC952431FAE for ; Tue, 8 May 2012 13:13:33 -0700 (PDT) Received: by guru.guru-group.fi (Postfix, from userid 501) id 2DE6868021; Tue, 8 May 2012 23:13:28 +0300 (EEST) From: Tomi Ollila To: Charlie Allom , notmuch@notmuchmail.org, Ali Polatel Subject: Re: [PATCH] ruby: extern values in ruby defs.h In-Reply-To: <1336481467-66356-1-git-send-email-charlie@mediasp.com> References: <1336481467-66356-1-git-send-email-charlie@mediasp.com> User-Agent: Notmuch/0.12+181~g650dcc2 (http://notmuchmail.org) Emacs/23.3.1 (x86_64-unknown-linux-gnu) X-Face: HhBM'cA~ MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-BeenThere: notmuch@notmuchmail.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: "Use and development of the notmuch mail system." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 May 2012 20:13:35 -0000 On Tue, May 08 2012, Charlie Allom wrote: > Currently, building on OSX complains about linking duplicate symbols. This > fixes the error. > --- I just spent some time looking out this declaration/definition thing -- it is not easy to find proper documentation... Finally, I was reading this: http://www.open-std.org/jtc1/sc22/wg14/www/docs/C99RationaleV5.10.pdf (warning (goatse class), pdf converted from word document ;) At the end of page 33 is interesting (also beginning of 34 and it is good to start from middle of page 32) Those mention 4 different way 'external linkage' is handled in pre-89 compilers... Standards-compliant (c99, at least) compilers should handle this is a combination of 'Strict Ref/Def' and 'Initialization' model. IIUC this means that if variable is defined (I mean declared) as int i; It is a tentative definition; There can be many of these seen by c compiler while compiling c files and when linking is done there will be one storage allocated for this variable. There can be (at most) one definition like int i = 0; in source code, even another 'int i = 0;' is not allowed according to the standard -- some compilers may make this work (and even the case where there is 'int i = 1;') But, there are also compilers that only allow 'Strict Ref/Def' model; IIUC then there can be only one 'int i;' (or 'int i = 0;') -- and all others (declarations) needs to be in format 'extern int i;'. The 'Strict Ref/Def' model is the model specified in K&R. All of that said, LGTM! Tomi > bindings/ruby/defs.h | 46 +++++++++++++++++++++++----------------------- > 1 files changed, 23 insertions(+), 23 deletions(-) > > diff --git a/bindings/ruby/defs.h b/bindings/ruby/defs.h > index 81f652f..bd124cc 100644 > --- a/bindings/ruby/defs.h > +++ b/bindings/ruby/defs.h > @@ -24,31 +24,31 @@ > #include > #include > > -VALUE notmuch_rb_cDatabase; > -VALUE notmuch_rb_cDirectory; > -VALUE notmuch_rb_cFileNames; > -VALUE notmuch_rb_cQuery; > -VALUE notmuch_rb_cThreads; > -VALUE notmuch_rb_cThread; > -VALUE notmuch_rb_cMessages; > -VALUE notmuch_rb_cMessage; > -VALUE notmuch_rb_cTags; > - > -VALUE notmuch_rb_eBaseError; > -VALUE notmuch_rb_eDatabaseError; > -VALUE notmuch_rb_eMemoryError; > -VALUE notmuch_rb_eReadOnlyError; > -VALUE notmuch_rb_eXapianError; > -VALUE notmuch_rb_eFileError; > -VALUE notmuch_rb_eFileNotEmailError; > -VALUE notmuch_rb_eNullPointerError; > -VALUE notmuch_rb_eTagTooLongError; > -VALUE notmuch_rb_eUnbalancedFreezeThawError; > -VALUE notmuch_rb_eUnbalancedAtomicError; > - > -ID ID_call; > -ID ID_db_create; > -ID ID_db_mode; > +extern VALUE notmuch_rb_cDatabase; > +extern VALUE notmuch_rb_cDirectory; > +extern VALUE notmuch_rb_cFileNames; > +extern VALUE notmuch_rb_cQuery; > +extern VALUE notmuch_rb_cThreads; > +extern VALUE notmuch_rb_cThread; > +extern VALUE notmuch_rb_cMessages; > +extern VALUE notmuch_rb_cMessage; > +extern VALUE notmuch_rb_cTags; > + > +extern VALUE notmuch_rb_eBaseError; > +extern VALUE notmuch_rb_eDatabaseError; > +extern VALUE notmuch_rb_eMemoryError; > +extern VALUE notmuch_rb_eReadOnlyError; > +extern VALUE notmuch_rb_eXapianError; > +extern VALUE notmuch_rb_eFileError; > +extern VALUE notmuch_rb_eFileNotEmailError; > +extern VALUE notmuch_rb_eNullPointerError; > +extern VALUE notmuch_rb_eTagTooLongError; > +extern VALUE notmuch_rb_eUnbalancedFreezeThawError; > +extern VALUE notmuch_rb_eUnbalancedAtomicError; > + > +extern ID ID_call; > +extern ID ID_db_create; > +extern ID ID_db_mode; > > /* RSTRING_PTR() is new in ruby-1.9 */ > #if !defined(RSTRING_PTR) > -- > 1.7.5.4 > > _______________________________________________ > notmuch mailing list > notmuch@notmuchmail.org > http://notmuchmail.org/mailman/listinfo/notmuch