How to use c program macros in calc ?

I’m new to libre office. I had a basic knowledge on using office. I like to take this to the next level i.e Using C macros in cals. Could any one plz guide me from here

I was very upset when Excel 5 came about for Mac OS 9. It refused to support XCMD modules written in C for Excel 4. I have been looking carefully for a return of C support but nothing has appeared. Perhaps the LO folks will do something.