How to change matlab stores image data for C++

Hello everybody i am writing a Program using C++ with OpenCV library! and I am using a function generated by Matlab Mex which takes an image and returns values! it look something like this   array=findsomething(image);//matlab function the image is a OpenCV variable which called Mat! this Mat stores the pixels in a unsigned char array as BGR. while Matlab function stores the pixels in RGB array. converting the data between the OpenCV variable and the Matlab Function variable means copying each pixel from the first variable Mat into Unsigned Char *array(this is the Matlab function Variable) which takes a really long time for each i call an image from the camera. is there a way to change how Matlab stores and handles the image data to become BGR ?