The func_insert function dynamically inserts a named function into the server's table of functions. This function should only be called during the Init stage.
FuncStruct *func_insert(char *name, FuncPtr fn);
Returns the FuncStruct structure that identifies the newly inserted function. The caller should not modify the contents of the FuncStruct structure.
char *name is the name of the function.
FuncPtr fn is the pointer to the function.