sandeep satpal <sandeep(at)it(dot)iitb(dot)ac(dot)in> writes:
> Whenever a function get called it receive one parameter
> as
> PG_FUNCTION_ARG ( as in nbtcompare.c )
> I am not getting how it is interpreted and how it is used ??
It's a pointer to a struct containing the actual arguments.
You might find it helpful to read src/backend/utils/fmgr/README
which is old but still accurate.
regards, tom lane