[Qt-interest] Problem with linking external libraries (Win32)

[Markus Straub]

John McClurkin wrote:
> Markus Straub wrote:
>> Dear list,
>>
>> I recently bumped into a problem when trying to compile and run a 
>> project on Win32 which was developed on Linux and fail to solve it.
>>
>> I seem to be unable to use the DLL provided by InterSense (isense.dll) 
>> under Win32, whereas I have no problems with libisense.so under Linux.
>>
>> In both OSes I copied the shared library to the common path, 
>> /usr/local/lib and c:\windows\system32 respectively. Compiling and 
>> linking the same code within QtCreator also works fine on both, even 
>> without the LIBS directive in the .pro file
>> (win32:LIBS += c:\windows\system32\isense.dll). All required headers are 
>> included as well.
>>
>> The problem arises when running the program: on Windows I only get the 
>> message "Could not load isense", on Linux it just works.
>>
>>
>> Now I am wondering what I am missing, why is my program not able to find 
>> the dll at runtime (if that is what the error message means).
>> A small testprogram compiled with Visual Studio 6 could successfully use 
>> isense.dll, so I guess the problem is caused by my project configuration.
>>
>>
>> Any hints would be appreciated.
>>
>> Best regards,
>> Markus Straub
> This is probably a compiler issue. On Linux, the InterSense library was 
> undoubtedly compiled with gcc, the same compiler used for Qt. For 
> Windows, the InterSense libraries were probably compiled with Visual 
> Studio. You describe your windows project as a Win32 project, so I'm 
> assuming you are using MinGW. You can't link libraries compiled with 
> Visual Studio (or Borland for that matter) with programs compiled with 
> MinGW.
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Finally I solved the problem:

The .dll was definitely compiled with Visual Studio but this was not the 
problem. It now happily works with my program that I compile with MinGW 
in QtCreator. The solution was to not use LoadLibrary() but 
LoadLibraryA() for loading the .dll .. so the root of the problem was 
character encoding.