Hi, On Feb 22, 2018, at 9:31 PM, Michael Paquier <michael@xxxxxxxxxxx> wrote: > PG_GETARG_NUMERIC(), no? That function returns an object of datatype “Numeric” which still requires some (not immediately obvious) conversation to a double (or whatever primitive C type). > When working on implementing your own data > types or when hacking out functions which manipulate arguments of an > existing datatype, looking at the input and output functions help a > lot. In your case, numeric_in and numeric_out in > src/backend/utils/adt/numeric.c is full of hints. I spent an hour diving into the code out of curiosity. I found useful functions like this: double numeric_to_double_no_overflow(Numeric n) They’re available from the PostgreSQL main source code, but not exposed in the public headers. (Maybe I was missing something.) There was enough there where I could see a way to copy/paste or otherwise link to those methods, but as Tom pointed out, implicit coercion handles what I need so I’ll stick with that. Cheers, Demitri
