Using the C Math Library

Assigning Values to a Structure Field 

To assign an initial value to a field (creating the field if it doesn't exist) or modify the value of an existing field, use mlfIndexAssign(). For example, to change the description field of the seventeenth image, you'd write this code:

mlfIndexAssign(&images,
               "(?).description",
               mlfScalar(17),
               mxCreateString("Cloned sheep embryo #1"));

Note that you must pass the array being modified to mlfIndexAssign() as an mxArray **, rather than the mxArray * that mlfIndexRef() requires.

images(17).description = 'Cloned sheep embryo #1' performs the same operation in MATLAB.

Accessing the Contents of a Structure Field

Assigning Values to Elements in a Field