no error numbers - only error messages?

Hello,

I'm having the following problem:
I'm talking to PostGreSQL using a variety of bindings (libpq, PHP), all
non-interactive.
If something goes wrong with one of my queries, I can ask PostGreSQL
to give an errormessage.
Unfortunately, errormessages are hard to parse. MySQL for example, works
around that problem by providing an error number on request, but as far
as I know, PostGreSQL doesn't.

Did I overlook something or does PostGreSQL really have no error
numbers? If not, is there any way I reliably parse the error messages?

Thanks for any help,

Sander

P.S. I'm not subscribed to the list, so please CC me when replying.
Thanks!