Is this fixed in the 7.4 release?

I am having troubles the following code on PostgreSQL 7.3.1.

[snip]
res = PQexec(conn, "SELECT '' AS blah");
if (!res)
{
fprintf(stderr, "SELECT command failed: %s\n",
PQerrorMessage(conn));
PQclear(res);
exit_nicely(conn);
}

fprintf(stdout, "OID(%d)\n", PQftype(res, 0));

PQclear(res);
[/snip]

Basically, I am asking the program to return me the field type of the
first column in the command "select '' AS blah". I was expecting
something like a CHAROID, but the return value is UNKNOWNOID (OID(705)).
D'oh. And I also tried "select ' ' AS blah", as well as "select 'A' AS
blah", they all returned me UNKNOWNOID (OID(705)) for the first column.

Is this a bug? If it is, is it fixed in 7.4 release possibly?

--
Wei Weng
KenCast Inc.