There was an error loading the library

Dear all,

I put the compiled dll file (written in C) in 'C:\Program Files\MATLAB\R2011b\extern\include\

I have a problem when I tried to load the library using the following command:

hfile = [matlabroot '\extern\include\dll\spinapi.h']; loadlibrary('spinapi', hfile)

it gave me the following error message:

Error using loadlibrary (line 421) There was an error loading the library "spinapi" The specified module could not be found.

Caused by: Error using loaddefinedlibrary The specified module could not be found.

My operating system is 64bit Win7, matlab is 64bit version, compiler is Microsoft Software Development Kit (SDK) 7.1, which is recommended in http://www.mathworks.com/support/compilers/R2011b/win64.html

Does anyone know what the problem is? I almost tried every method that I could find in google. But they didn't help. I am so deperated......

One thing made me very confused was that, I did exactly the same in my old computer, its operating system is 32bit Windows XP, matlab is R2009a 32bit version, compiler is lcc-win32 C, and it could load the library without any error!!!

I will be very thankful to anyone who can help me.

Best Regards, Kit

[Peter]

Open your spinapi.dll in Dependency Walker (google: depends22_x64.zip). You will see which .dll files need to be copy or installed with your spinapi.dll

Answer 1

[Philip Borghesani]

I suggest using Dependency Walker to profile the loadlibrary call.

1. Open .../bin/win64/matlab.exe with Dependency Walker.
2. Start profiling
3. Wait for MATLAB to come up and clear the log window
4. Issue the loadlibrary command and examine the log in dDependency Walker for error messages.

The problem is probably a missing runtime library or other dll dependency.

Answer 2

[Walter Roberson]

'C:\Program Files\MATLAB\R2011b\extern\include\' is not on my matlabpath, so I cannot think of any reason MATLAB would think to look there for .dll files. Did you add that directory to your matlabpath ?

[Kit Mai]

Hey Walter,

I did add that directory to my matlabpath.

[Walter Roberson]

Are you able to load the sample library using the form showed in "addpath example" in http://www.mathworks.com/help/techdoc/ref/loadlibrary.html ?

[Kit Mai]

yes, I am able to load the 'Using alias Example' in http://www.mathworks.com/help/techdoc/ref/loadlibrary.html

any ideas?

Answer 3

[Kit Mai]

I tried the following command again, and it gave me a slightly different error message:

>> addpath(fullfile(matlabroot,'extern','include','dll'))

>> loadlibrary spinapi64 spinapi.h

Error using loadlibrary (line 421)

There was an error loading the library "C:\Program Files\MATLAB\R2011b\extern\include\dll\spinapi64.dll"

C:\Program Files\MATLAB\R2011b\extern\include\dll\spinapi64.dll is not a valid Win32 application.

Caused by: Error using loaddefinedlibrary

C:\Program Files\MATLAB\R2011b\extern\include\dll\spinapi64.dll is not a valid Win32 application.

What does it mean? Why is it looking for a valid Win32 application? Shouldn't it be 64bit?

[Walter Roberson]

Hmmmm... I would wonder if you are really using the 64 bit version of MATLAB. Try giving the command

mexext

and see if it says mexw32 (32 bit MATLAB) or mexw64 (64 bit MATLAB)

[Kit Mai]

God, it says mexw64!

[Walter Roberson]

Hmmm, I don't know; perhaps someone else will have an idea.

Mumble mumble... thunk file related ???

[Kit Mai]

???

what do you mean?

[Philip Borghesani]

Microsoft uses the same error messages for both 32 and 64 bit Windows. In their infinite wisdom they consider 64 bit programs to be written to the win32 api. There is no win64 api.

Answer 4

[Kit Mai]

by the way, the dll is coming from here: http://www.spincore.com/support/spinapi/SpinAPI_Main.shtml

The latest 64bit SpinAPI package.

64bit version of matlab is loading 64bit dll, but it does not work.......why?

Answer 5

[Venugopal]

I have the similar problem of Kit Mai...

Kit Mai.. did u find some solution??

Answer 6

[dpsycho]

Did you happen to have crashed before this happened?

I have the same thing. At some point everything worked, matlab crashed, and then could not load the library. Rebooted even and still no luck.