Biometric matching with futronic sdk using nodejs server - c

Question

I have successfully taken bio-metric prints and posted to the node server using the futronic sdk. I want to be able to use this library likewise for matching in the server because that's where the bio-metric prints for all users are stored. I stubbled upon the node-ffi library that helps define equivalent C functions that I have exported and compiled it down to a .dll file.
Now the challenge here is that I have tried to port the ftrAnsiSDK functions but the ftrScanAPI.dll and the ftrAnsiSDK.dll file could not be compiled together. It gives this error:
...collect2.exe [Error] ld returned 5 exit status
When I compile and export the functions that are not dependent on these two libraries, my code works fine and the functions are easily exported and used in the node server. Please can any one give me a hint?
Here is the link to the repo. It consists of the lib and .dll library that is been used.
For the server code here is a snippet of what I am trying to achieve:
var libm = ffi.Library('lib/visystem', {
'HelloWorld': [ 'void', [] ],
'PrintErrorMessage': [ 'void', ['int'] ],
'CaprureImage': [ 'int', ['int','int','int'] ]});
The HelloWord and PrintErrorMessages are methods that I used as a test case to ensure the functions are being exported before I proceeded to the main functions (you can see the function definition in from the code in the repo.. ) that depends on the futronic lin and sdk.
I am currently using a 64-bit operation system and I installed the same program on a 32-bit machine to be sure, but it still did not compile and export the function. The code editor I am using is Dev++C.
Can anyone help or even give me hint on how to achieve this goal?

Answer 1

As a disclaimer, I'm not familiar with the Dev-C++ IDE or MinGW development.
However, after a cursory look at your github repo, according to your libvisystem.def file, it appears that the only functions that are exported by your DLL are:
HelloWorld
PrintErrorMessage
ReadTemplateFile
SaveBmpFile
SaveTemplateFile
This is also confirmed when looking at the libvisystem.a library header:
So you should probably start by manually add the rest of the exported functions in your dll.h to the def file, in a similar manner to the ones that are already there, and see if that changes anything.
NOTE:
I'm not sure whether the __declspec(dllexport) directive is ignored by the Dev-C++ compiler/linker and it uses the def file instead. Perhaps others on SO have an idea.