MATLAB Answers


Mex file-using c functions

Asked by seldeeno
on 21 Apr 2013

Hello all,

I have one question: I have a matlab wrapper that calls another C file that has some functions that I want to pass data to from Matlab and get results back to Matlab. But not successful!

The complication is: Whenever I compile the first c file (wrapper), it gives an mexw64 file (although I was told it is a dll) and when this happens and I just call this file Matlab cannot load this 2nd file that has the functions claiming that it is empty! Any ideas what am I doing wrong here?

For this second file (that has the functions) I was told to compile it like this:

gcc -c fcnsuite.c -DWINDOWS
dllwrap -o fcnsuite.dll fcnsuite.o

Using MingW, but it does not generate any dll and hence I get: dllwrap: no export definition file provided. Creating one, but that may not be what you want dllwrap: CreateProcess: No error

Any hints?




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2 Answers

Answer by Jan Simon
on 21 Apr 2013

MEXW64 files are DLLs, although they have a different file extension.

What about compiling the wrapper and the core functions together:

mex -O wrapper.c fcnsuite.c

? Then the code of the fcnsuit is included in the wrapper DLL.


Actually I tried to compile fcnsuite.c using mex and then it complains that it is not like the wrapper! Why is not able to locate that dll for fcnsuite.c although I have a copy of its dll that was created on another windows system?

To be able to use the MEX command, you need to provide at least one C-file that contains an entry-point with the signature:

void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]);

Do you have this in fcnsuite.c?

Also, it's not clear what you mean by "Why is not able to locate that dll for fcnsuite.c...". How do you use it in MATLAB, and what is the error that you see?

I have this in the interface that has my mexfunction (named "mlbsuite.c"). The fcnsuite.c contains all the functions but when I call my mlbsuite later after execution it says that the function that I call is not in the library:

"procedure g06 not found in library file!Error using mlbsuite failed to load procedure"

Answer by seldeeno
on 23 Apr 2013

Ok people I got it to work. Actually I had to create the dll of the function using a command like: mbuild file1.c file1.exports with function names in this file1.exports and that did the trick

Thank you all for your comments!


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