function returns whether a code is checked as part of a check box
field's selections. The check_box_field_name
is the name of an alphanumeric field that is represented on a form as a check box. The code
is a string expression containing the code to be checked.
The codes of CSPro check boxes are placed at uniformly spaced offsets based on the size of the code. For example, if the check box field has a length of 20 and each code has a length of 2, then the function checks positions 1-2 for the code, then positions 3-4, and so on until positions 19-20.
The function returns a logical value of 1 (true) if the code was found (at the correct offset) in the check box field and 0 (false) otherwise.