Math copy api

Hi ,

I need to know the Syntax of Using Math COPY API in C BSFN , When the requirement is to copy the DOCO from Table F56XXXXX to DOCO element placed in the data structure D56POCA.

I would like some one to help in framing the syntax below. I am not aware of first part of syntax below.

MathCopy("How to use DOCO from F56XXXXX",&lpdsDSD56POCA->mnOrderNumber,);

Regards,
Sreejith