Can't load library function from dll

Hello!

Question first:

Does anyone have an idea on why the funciton I need is not loaded?

Explanation:

I am working with a sensor and I need to call a function called

GetOpticalProbe

This function is described in an API reference document the manufacturer provided me with.

I do have all the files, .dll and .hs. namely

CHRocodile.dll

CHRocodileLib.h

CHRocodileLibErrorDef.h

CHRocodileLibPluginDef.h

CHRocodileLibSpecialFunc.h

After examining the CHRocodileLib.h I found nothing named GetOpticalProbe. I did however found something in CHRocodileLibSpecialFunc:

inline Res_t GetOpticalProbe(arguments)

and includes to some of the other heathers near the beginning:

#include "CHRocodileLib.h"

#include "CHRocodileLibErrorDef.h"

From the matlab documentation of loadlibrary, I understood that when loading a library that has includes, the other heathers should be added to the command:

loadlibrary('mylib','mylib.h','addheader','header2')

So I tried loading it like this:

loadlibrary(fullPathToDll, fullPathToCHRocodileLibSpecialFunc.h, 'addheader', 'CHRocodileLib', 'addheader', 'CHRocodileLibErrorDef')

But after executing loadlibrary, there is no sign of the function I need:

libfunctions CHRocodile

Functions in library CHRocodile:

...

GetNext...

GetOutput...

GetResponse...

...

loadlibrary does give me some warnings like

Warning: The data type 'FcnPtr' used by function RegisterSomethingCallback does not exist.

I do not read C/C++ so I find it rather hard to read any of the .h files.

Thanks in advance!

P.S.: I edited some of the names as I am not sure they are public.

Answer 1

[Aiswarya]

Hi,

I understand that you are not able to load a particular function 'GetOpticalProbe' in your CHRocodile library.

One of the possible ways to resolve this issue is to specify the storage class information of the function by using "__declspec". This can be done as follows:

__declspec( dllimport )  inline Res_t GetOpticalProbe(arguments)

Then you can use the loadlibrary function to load the dllibrary and then call the function with arguments using the function "calllib" (https://www.mathworks.com/help/matlab/ref/calllib.html)

calllib('CHRocodile','GetOpticalProbe',arg1,arg2,…,argn);

You may also refer to this MATLAB answer to know more about this issue:

https://www.mathworks.com/matlabcentral/answers/156064-problem-with-c-dll-in-matlab-the-function-was-not-found-in-the-library?s_tid=answers_rc1-2_p2_Topic

Hope this helps!

[Andrés Aguilar]

Aiswarya, thank you very much for your reply.

I ended up achieving the same result by sending direct commands using a proprietary protocol of the manufacturer.

I'll try to sets your method though once I unentangle myself from other stuff.