How to edit "mexopt.bat" file in Matlab?

I have Matlab R2014b and OpenCV 2.4, i have been trying to use ViolaJones Face Detection toolbox, but i have some troubles. I've searhced the problem and found a solution that suggest edit mexopt.bat file. What the real problem is here

The Matlab command

fullfile(prefdir, 'mexopts.bat')

returns

C:\Users\simit\AppData\Roaming\MathWorks\MATLAB\R2014b\mexopts.bat

but I can't find the file when I go to the path. How can I find the mexopts.bat file and edit it?

Solution

I have R2015b installed. I searched my computer for a mexopts.bat file, and found it in folders related to code I have from 2012-2013, but not in the new MATLAB install folder. For this reason I believe it's not a part of the standard MATLAB installation, which is probably why you didn't find it.

According to this thread it seems that the mexopts.bat file is no longer used in MATLAB starting R2014a, and instead you should look for these files:

mex_C_win32.xml
mex_C_win64.xml
MBUILD_C_win32.xml
MBUILD_C_win64.xml

If you are still convinced that you should find and edit a mexopts file, let me recommend you the Everything Search Engine to look for files on your hard-drive.