Re: understanding Datum -> char * -> Datum conversions

Casting doesn't do it. Use text_out() to produce a null-terminated C
string from a text Datum, and use text_in() to create a new text Datum
after you've modified the string.

By the way, I know there are a bunch of macros for tranforming to and
from Datum, but whenever I use them I have to figure out again exactly
how to do it.

Is there some documentation on the set of macros and what they do (or
some other means of describing how one translates arguments and return
values between internal form and "useful" programming form)?

Thanks for your help.

Cheers,
Brook