Size mismatch when using Mex function?

I've converted a piece of matlab code to C/mex in order to improve performance of computationally intensive step. Within the algorithm, I look for a value within an array as follows:

 Ck = find(COM==Cnew);

When I do this, I get the following error running the mex function..

Sizes mismatch: [1][5000] ~= [1][1]. More information Error in ClusterMex (line 73) Ck = find(COM==Cnew);

I declare Cnew at the top of a while loop as Cnew=[] in order to set its type for the C compilation and it seems to be reading it as such but when it tried to do this comparison, it is unable in the mex function.

Thanks for the help!

[Walter Roberson]

What is the declared size of Ck? Did you use coder.varsize() for it?