GENERAL - How to Declare Functions Containing OUT PArameters?

I'm having some difficulty getting plpgsql to recognize a function with
a couple of OUT parameters. I'm either declaring the function
incorrectly, making the call to it in the wrong way or my program is
simply possessed by evil spirits. I'm using Postgres 8.1.5.
What appears to be happening is that it's declaring the function as if
it returned a record and had only two parameters, but I'm trying to
call it with four parameters, with two of them being OUT parameters. So
the compiler sees two different versions of the function and refused to
do anything more. The example below shows the problem, but it's just
something to exercise the function calls and generate the error. Can
anyone spot the screw-up in this little example? (the error message is
listed below in the block comment)
TIA,
-Bill Thoen
CREATE OR REPLACE FUNCTION fishy( s1 text, s2 text, OUT n integer, OUT f
real ) AS $$
DECLARE
c integer;
BEGIN
c := length( s1 );
n := length( s1 || s2 );
f := c::real / n::real;
END;
$$ LANGUAGE plpgsql;
CREATE OR REPLACE FUNCTION main() RETURNS VOID AS $$
DECLARE
str1 text;
str2 text;
num integer := 0;
fnum real := 0.0;
BEGIN
str1 := 'One fish, two fish';
str2 := 'Shark fish, No fish';
SELECT fishy( str1, str2, num, fnum) ;
RAISE NOTICE 'fishy() analysis: % %', num, fnum;
END;
$$ LANGUAGE plpgsql;
SELECT main();
/* ERROR MESSAGE
psql:ex-out-fail.sql:28: ERROR: function fishy(text, text, integer,
real) does not exist
HINT: No function matches the given name and argument types. You may
need to add explicit type casts.
CONTEXT: SQL statement "SELECT fishy( $1 , $2 , $3 , $4 )"
PL/pgSQL function "main" line 9 at SQL statement
And when I run df from the pgsql command line, it shows up like this:
| fishy | record | text, text
*/

Hello
PostgreSQL use OUT params very untypically. You can't to directly to
join OUT parameter with some variable. It isn't possible.
please, try
CREATE OR REPLACE FUNCTION foo(a int, b int, OUT c int, OUT d int)
RETURNS record AS $$
BEGIN
c := a + 1;
d := b + 1;
RETURN;
END;
$$ LANGUAGE plpgsql strict immutable;
CREATE OR REPLACE FUNCTION use-foo()
RETURNS void AS $$
DECLARE r record AS $$
BEGIN
r := foo(10,20);
RAISE NOTICE '% %', r.c, r.d;
END;
$$ LANGUAGE plpgsql immutable;
SELECT use-foo();
Regard
Pavel Stehule
2010/7/14 Bill Thoen :
>

On Wed, 2010-07-14 at 12:21 -0600, Bill Thoen wrote:
First, 8.1.x is EOL as of November. You need to upgrade.

You are passing four IN paramaters. The out paramaters are used in
return are they not?
Joshua D. Drake

"Joshua D. Drake" writes:
You'd need to do something like
SELECT * INTO num, fnum FROM fishy(str1, str2) ;
OUT parameters in PG are just syntactic sugar for defining a
record-returning function. The call syntax still works as if you'd
written CREATE FUNCTION foo (IN-parameters-only) RETURNS some-record-type.
regards, tom lane

Thanks guys. I think I see now. I was thinking it was a more transparent
pass-by-value / pass-by-reference thing.
Anyway I solved my problem by going back into my comfort zone and
explicitly return a record and I'm not using OUT parameters. They're
aren't what I thought they were and I'm working on a tight schedule, so
I don't have much toim m eto explre. The compiler seems happier without
them, and when it's happy, I'm happy.