I just found this thread:<br /><br /><a
href="http://archives.postgresql.org/pgsql-general/2011-11/msg00424.php">http://archives.postgresql.org/pgsql-general/2011-11/msg00424.php</a><br
/><br/>So I'll use the same workaround.<br /><br />Nothing to see here, folks, move along....<br /><br />d<br /><br
/><divclass="gmail_quote">On Fri, Nov 18, 2011 at 11:17 AM, David Zwarg <span dir="ltr"><<a
href="mailto:dzwarg%2Bpostgis@azavea.com">dzwarg+postgis@azavea.com</a>></span>wrote:<br /><blockquote
class="gmail_quote"style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Hello,<br /><br />I have been
workingwith the PostGIS developers, and I'm implementing a facility to use 'callback' functions to process cells in a
rasterimage.<br /><br />I have implemented this behind the scenes as a C function that calls a provided sql
regprocedurewith OidFunctionCall*. I have been reading the docs, and it states that "Note that neither arguments nor
resultare allowed to be NULL."<br /><br />In this use case, there are legitimate reasons to return NULL from a
'callback'function -- is there an alternative method that I should use, instead of OidFunctionCall*?<br /><br
/>Thanks,<br/><font color="#888888">David<br /></font></blockquote></div><br />
