What is the difference between RETURNS `SETOF integer` and RETURNS TABLE(name int)`?

Question

Given the two definitions below, is there any difference?

CREATE FUNCTION foo(OUT foobar int4)
RETURNS SETOF int4
AS 'MODULE_PATHNAME', 'foo'
LANGUAGE C STRICT VOLATILE;

And,

CREATE FUNCTION foo()
RETURNS TABLE(foobar int4)
AS 'MODULE_PATHNAME', 'foo'
LANGUAGE C STRICT VOLATILE;

That is to say is there a difference between the "Result data type" as displayed with \df between

• TABLE(foobar integer)
• and, SETOF interger where the Argument data types includes OUT foobar integer

Answer 1

The docs say this on CREATE FUNCTION

The name of an output column in the RETURNS TABLE syntax. This is effectively another way of declaring a named OUT parameter, except that RETURNS TABLE also implies RETURNS SETOF.