Mailing-List: contact cygwin-help@sourceware.cygnus.com; run by ezmlm List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@sources.redhat.com Delivered-To: mailing list cygwin@sources.redhat.com X-Authentication-Warning: hp2.xraylith.wisc.edu: khan owned process doing -bs Date: Wed, 11 Jul 2001 16:03:15 -0500 (CDT) From: Mumit Khan Reply-To: Mumit Khan To: Robert Cordingley cc: cygwin@cygwin.com Subject: Re: error trying to build very simple dll In-Reply-To: <5.1.0.14.2.20010711145916.00aa2d60@earth.he.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII On Wed, 11 Jul 2001, Robert Cordingley wrote: > Trying to build a very simple little dll, I get the following error: > > $ dlltool --def gettz.def --output-exp gettz.exp --output-lib gettz.a > --dllname gettz.dll > $ gcc -c gettz.c > $ ld -o gettz.dll gettz.exp gettz.o First rule of using gcc on any platform -- unless you have a very good reason and know what you're doing, never use "ld" to link, but *always* use gcc or one of the other compiler drivers. Following this rule is even more important on platforms such as linux (if you want correct dynamic linker linked in), Cygwin (if you want correct libraries linked in), etc. That said, you can do the following to build your DLL. $ gcc -c gettz.c $ gcc -shared -o gettz.dll -Wl,--out-implib,gettz.a gettz.def gettz.o I'm assuming that you already have a proper gettz.def; if not, you can either (1) use __declspec(dllexport), or (2) create one by hand. > ld: warning: cannot find entry symbol _mainCRTStartup; defaulting to 00401000 > gettz.o(.text+0xc):gettz.c: undefined reference to `time' > gettz.o(.text+0x20):gettz.c: undefined reference to `localtime' > gettz.o(.text+0x28):gettz.c: undefined reference to `_imp___tzname' These show up because you are using ld, and it doesn't know what system libraries to link in. Regards, Mumit -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Bug reporting: http://cygwin.com/bugs.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/