Questions about the internal of fastpath function call

Hi,<br /><br />I am reading the source code of fastpath to understand the internal of fastpath. I can not understand
howdoes it send result to the client, I hope somebody can help me on this.<br /><br />I see it call it invoke the
functionin <br /><br />HandleFunctionRequest()<br />  -> retval = FunctionCallInvoke(&fcinfo);<br />  ->
SendFunctionResult(retval,fcinfo.isnull, fip->rettype, rformat);<br />              ->OidOutputFunctionCall()  
<br/>                      -> OutputFunctionCall()<br />                                ->  result =
DatumGetCString(FunctionCall1(flinfo,val));<br />                                       -> result =
FunctionCallInvoke(&fcinfo);<br/><br />but I can not see in where it send the tuples to the client, instead it 
invokeFunctionCallInvoke again. Can anyone tell me how it copy the tuples and send it to the client.<br /><br />Thanks
alot.<br /><br />Clipper <br /> <br />  <br />