(PHP 4 >= 4.0.1, PECL yaz:0.9-1.0.9)
yaz_errno — Returns error number
Returns error for target (last request). A positive value is returned if the target returned a diagnostic code; a value of zero is returned if no errors occurred (success); negative value is returned for other errors targets didn't indicate the error in question.
yaz_errno() should be called after network activity for each target - (after yaz_wait() returns) to determine the success or failure of the last operation (e.g. search).