From owner-freebsd-questions@FreeBSD.ORG Sat Mar 15 02:49:33 2008 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 87162106566B for ; Sat, 15 Mar 2008 02:49:33 +0000 (UTC) (envelope-from bc979@lafn.org) Received: from zoot.lafn.org (zoot.lafn.ORG [206.117.18.6]) by mx1.freebsd.org (Postfix) with ESMTP id 3F1228FC13 for ; Sat, 15 Mar 2008 02:49:33 +0000 (UTC) (envelope-from bc979@lafn.org) Received: from [10.0.1.2] (pool-71-116-247-93.lsanca.dsl-w.verizon.net [71.116.247.93]) (authenticated bits=0) by zoot.lafn.org (8.13.6/8.13.4) with ESMTP id m2F2nT0X001168 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO); Fri, 14 Mar 2008 19:49:30 -0700 (PDT) (envelope-from bc979@lafn.org) Message-Id: From: Doug Hardie To: Derek Ragona In-Reply-To: <6.0.0.22.2.20080314202817.025de470@mail.computinginnovations.com> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v919.2) Date: Fri, 14 Mar 2008 19:49:29 -0700 References: <6.0.0.22.2.20080314171533.023f7c88@mail.computinginnovations.com> <511EC772-36FD-4799-B4A1-3AE690B6D048@lafn.org> <6.0.0.22.2.20080314202817.025de470@mail.computinginnovations.com> X-Mailer: Apple Mail (2.919.2) X-Virus-Scanned: ClamAV 0.88.7/6238/Fri Mar 14 19:28:24 2008 on zoot.lafn.org X-Virus-Status: Clean Cc: freebsd-questions Subject: Re: C compiler issue perhaps? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 15 Mar 2008 02:49:33 -0000 On Mar 14, 2008, at 18:31, Derek Ragona wrote: > At 06:56 PM 3/14/2008, Doug Hardie wrote: >> There is no code running at that point. Its just sitting there >> waiting for me to enter a gdb command. >> >> >> On Mar 14, 2008, at 15:16, Derek Ragona wrote: >> >>> At 05:10 PM 3/14/2008, Doug Hardie wrote: >>>> I have a program I was testing with gdb. I was trying to figure >>>> out >>>> why c.rmonths was always zero when it should have been 6. Stepped >>>> through using the gdb n command. Here is the output: >>>> >>>> (gdb) >>>> 215 c.rmonths = (edate - tdate) / >>>> toMONTHS; >>>> (gdb) >>>> 223 c.dial_in = u.dial_in[0]; >>>> (gdb) >>>> 224 c.dsl = u.dsl[0]; >>>> (gdb) p c.rmonths >>>> $1 = 0 >>>> (gdb) p c >>>> $2 = {fa = 0, pwp = 0, disp_email = 0, imonths = 0, rmonths = 6, >>>> type = 73 'I', cd = 0 '\0', dial_in = 82 'R', dsl = 0 '\0', >>>> dsl_kit = 0 '\0', ip = 0 '\0', domain = 0 '\0', n_domain = 0 >>>> '\0', >>>> renewal = 89 'Y', program = "I\000\000"} >>>> (gdb) p c->rmonths >>>> $3 = 6 >>>> (gdb) p c.rmonths >>>> $4 = 6 >>>> >>>> >>>> Notice, the first time i print it its zero. The second time its 6. >>>> What gives here? I have seen this before but couldn't pin it down. >>>> The program is not compiled with any optimization. It is in a >>>> shared >>>> library though. >>> >>> It is hard to tell without the code you used. I would put some >>> printf's in the code and see what and when that variable gets set to >>> in actual running code. >>> >>> -Derek > > I understand it is waiting at a breakpoint in gdb. What I meant was > put printf's in your code and run the program and look at the > output. You can use fprintf's to stderr if your prefer and just > look at the stderr output. > > It is hard to diagnose what could be a compiler error, or a coding > error. Remember in C you can do many things you really shouldn't. > It is also advisable to run lint over your source code too. All that lint shows is it doesn't like comments using // and lots of errors in /usr/include files.