At 2006-09-11 10:25:22 +0200, pgdev@xs4all.nl wrote:
>
> What are we testing to be NULL here?
> Do we expect str to changed at line 1715
No. (Read the comment just above the function.)
The code is like this, starting from line 1703:
if (str == NULL && flinfo->fn_strict) return (Datum) 0;
That is, if the function is declared strict, and the argument (str) is
0, just return NULL straightaway. Then it sets up the fcinfo and calls
the function, and then:
...
/* Should get null result if and only if str is NULL */ if (str == NULL) { if (!fcinfo.isnull)
elog(ERROR, "input function %u returned non-NULL", fcinfo.flinfo->fn_oid); } else {
if(fcinfo.isnull) elog(ERROR, "input function %u returned NULL",
fcinfo.flinfo->fn_oid); }
This says: If the argument is NULL and the input function didn't return
a NULL, log an error; but if the argument is non-NULL and the function
returned NULL, log this other error. (Note that a function would set
fcinfo->isnull to indicate that it wants to return an SQL NULL, as
explained in $DOC/plhandler.html)
-- ams
