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From Fabian Jacquet <fabian.jacq...@gmail.com>
Subject Re: link error in release mode with Visual Studio 2008
Date Fri, 07 May 2010 10:02:43 GMT
Mh, maybe those symbols are in the DLL but not in the lib. To be in the lib,
it must have __declspec(dllexport) when compiling.
log4cxx use this define to do this:
#if defined(LOG4CXX_STATIC)
//   definitions used when building DLL
#elif defined(LOG4CXX)
#define LOG4CXX_EXPORT __declspec(dllexport)
//    definitions used when using DLL
#define LOG4CXX_EXPORT __declspec(dllimport)

So, "LOG4CXX_EXPORT __declspec(dllexport)" when compiling log4cxx.dll
"LOG4CXX_EXPORT __declspec(dllimport)" when including log4cxx.h from your

If for some reason, LOG4CXX_STATIC is defined, it's possible that some
symbols are not exported. But I don't know how it's possible.

If you don't use more than those 13 symbols maybe nothing is exported or
maybe the link don't use log4cxx.lib.
You can check the list of lib used by the linker like this:
Project properties>Linker>General>Show Progress = /VERBOSE:LIB
The linker will dump the lib list in the output window of visual studio when
compiling. Check that you have something like that:
1>    Searching [your directories]\log4cxx.lib:

I don't know any tools to check symbols. I think you could check with
notepad, you can search about "getLogger" by example but if you find it, I
don't know if you can conclude that the symbol is right exported. If you
don't find it, I think the problem comes from the lib :-)

On Fri, May 7, 2010 at 11:08, Jean-Denis Muys <jdmuys@mac.com> wrote:

> Thanks for answering. I wish the solution was that simple. I apologize for
> not explicitly mentioning it, but my project is - I think - set up
> correctly.
> That is:
> - both the Debug and Release configurations mention log4cxx.lib in its
> Linker>Input>Additional Dependencies
> - both the Debug and Release configurations mention a *different* directory
> in Linker>General>Additional Library Directories. They are different because
> they point to the Debug version and the Relase version of loc4cxx
> respectively (apache-log4cxx-0.10.0\projects\Debug
> and apache-log4cxx-0.10.0\projects\Release)
> Of course both configurations of log4cxx were previously built with no
> failure (from its Visual Studio project). They were built in "DLL" mode as
> explained on the log4cxx web site. While doing a static library version is
> on my todo list, I'd rather solve the present issue first.
> At this point in time, I suppose the 13 missing symbols are present in the
> Debug version of the log4cxx.lib stub library, but not in the Release
> version. How can I verify this hypothesis? What could explain that? How can
> I fix it?
> Another hypothesis might be that there is yet another dependency that needs
> to be set in Release mode only. This seems less plausible though. And what
> would it be?
> Again, thanks for you answer. Any other idea on how I could make progress
> on this issue?
> Regards,
> Jean-Denis
> On May 7, 2010, at 10:29 , Fabian Jacquet wrote:
> Hi,
> The project configuration is different between debug and release. In debug
> you certainly added log4cxx.lib in the field "Linker/Input/Additional
> dependencies" but you have a drop-down which select the configuration, if
> you switch to release, I think you don't have log4cxx.lib in "Additional
> dependencies" .
> Don't forget to add the directory of this lib in the field
> "Linker/General/Additional Library Directories"
> log4cxx.lib is not really a static lib. It's only the interface to the dll
> class and functions.
> I hope it help you.
> On Fri, May 7, 2010 at 04:00, Jean-Denis Muys <jdmuys@mac.com> wrote:
>> Hi,
>> I have a Visual Studio 2008 project using log4cxx that links (and runs)
>> fine in Debug mode using the Debug version of log4cxx, but fails to link in
>> Release mode using the release version of log4cxx. Here are the 13 undefined
>> symbols:
>> 1>------ Build started: Project: RepliKator04, Configuration: Release
>> Win32 ------
>> 1>Linking...
>> 1>   Creating library
>> z:\PCdev\RepliKator2004\RK_Demo_2004\plugins\RepliKator04.bundle\contents\windows\RepliKator04.lib
>> and object
>> z:\PCdev\RepliKator2004\RK_Demo_2004\plugins\RepliKator04.bundle\contents\windows\RepliKator04.exp
>> 1>RKConnector.obj : error LNK2001: unresolved external symbol
>> "__declspec(dllimport) public: static class
>> log4cxx::helpers::ObjectPtrT<class log4cxx::Level> __stdcall
>> log4cxx::Level::getTrace(void)" (__imp_?getTrace@Level@log4cxx@
>> @SG?AV?$ObjectPtrT@VLevel@log4cxx@@@helpers@2@XZ)
>> [...]
>> 1>RepliKator04 - 13 error(s), 0 warning(s)
>> ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped
>> ==========
>> As I am a Mac developer, not a Windows developer, I feel lost here. What
>> can I do to fix that issue? I really don't get why those symbols would not
>> be defined in Release mode.
>> Note that my project is not an application, but a Plugin for a third party
>> app.
>> I link against the DLL version of log4cxx. I'd rather use a static library
>> version, but I failed to build it so, and I could not find detailed
>> instructions on the net to do it.
>> So for the time being, I am mainly interested in understanding why these
>> link-time errors occur, and in how to fix them.
>> Thanks and regards.
>> Jean-Denis

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