Error Compilng C++ MEX File

Hello, I'm trying to develop a new MEX file and can only compile the file one time before an error appears. I can successfully compile the file from the MATLAB command prompt one time upon launch of MATLAB. Subsequent attempts to compile the file produce an error message

'myfile.mexa64' is locked by the MexLock API

The only solution I've found so far is to restart MATLAB. Any suggestions on how proceed? Or what is causing the error upon compilation? Everything I've read about locking Mex files refers to runtime functions, not compilation.

Thanks Keith

[Shubham Jadhav]

I had faced the similar issue and the reason is,I was running simulation in steps (which required "that" mex file) and I trying to mex for the same s-function.

Answer 1

[Jan]

The "MexLock API" is triggered by the command mexLock. If this is called inside the Mex-function, this file is locked. You have to release it by using an internal method, which calls mexUnlock. Without such a method, restarting Matlab is the only solution.

Perhaps this helps:

void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[]) {
  if (nrhs == 0) {
    mexUnlock();
    return;
  }
  ...
}

Now calling the MEX function without inputs unlocks it.

But, well, why do you lock the Mex at all?

[EDITED] If clear mex does not help also, please post more details. Do you compile the mex file in an UNC path? If so, try it on a drive with drive letter.

[Keith Sullivan]

I don't lock the file. mexLock is not called anywhere in the code. Is there another way to lock a file without explicitly calling mexLock?

[Jan]

See [EDITED]