I would like to have a C function and/or stored procedure that can accept a
null parameter value and return a non-null value. 

Thanks, Michael

	-----Original Message-----
	From:	D'Arcy" "J.M." Cain [SMTP:darcy@druid.net]
	Sent:	Monday, March 29, 1999 10:27 AM
	To:	lockhart@alumni.caltech.edu
	Cc:	neko@kornel.szif.hu; hackers@postgreSQL.org
	Subject:	Re: [HACKERS] NULL handling question

	Thus spake Thomas Lockhart
	> > I don't seek this in the source, but i think, all function, who
take a 
	> > NULL value as parameter can't return with a NOT NULL value.
	> > But why?
	> 
	> Postgres assumes that a NULL input will give a NULL output, and
never
	> calls your routine at all. Since NULL means "don't know", there is
a

	Actually, the problem is that it does call the function.  After it
	returns it throws away the result and so the effect is that the
function
	never gets called but in the meantime, the function has to deal with
	NULL inputs for nothing.  This has been hanging around since the
last
	release.  I looked at the dispatch code but it wasn't very clear
where
	we have to put the test to do this correctly.  Maybe we can get it
cleaned
	up before release this time.


	> strong argument that this is correct behavior.

	I agree but recently I said that there was no stored procedures in
PostgreSQL
	and someone corrected me pointing out that functions with no return
were
	in effect stored procedures.  Do the same arguments apply?  If a
procedure
	is passed a NULL argument, should the side effects be bypassed?

	-- 
	D'Arcy J.M. Cain <darcy@{druid|vex}.net>   |  Democracy is three
wolves
	http://www.druid.net/darcy/                |  and a sheep voting on
	+1 416 424 2871     (DoD#0082)    (eNTP)   |  what's for dinner.

Mon, 29 Mar 1999 11:53:10 -0600
Michael Davis <michael.davis@prevuenet.com>
RE: [HACKERS] NULL handling question