MysqlndUhConnection::getErrorString

 MysqlndUhConnection::getErrorString() is not only executed after the invocation of a user space API call which maps directly to it but also called internally. 
 
例1 MysqlndUhConnection::getErrorString() example
 

class proxy extends MysqlndUhConnection {
 public function getErrorString($res) {
   printf("%s(%s)\n", __METHOD__, var_export(func_get_args(), true));
   $ret = parent::getErrorString($res);
   printf("%s returns %s\n", __METHOD__, var_export($ret, true));
   return $ret;
 }
}
mysqlnd_uh_set_connection_proxy(new proxy());

printf("connect...\n");
$mysqli = new mysqli("localhost", "root", "", "test");
printf("query...\n");
$mysqli->query("WILL_I_EVER_LEARN_SQL?");
printf("errno...\n");
var_dump($mysqli->error);
printf("close...\n");
$mysqli->close();

 
上の例の出力は以下となります。
 
connect...
proxy::getErrorString(array (
  0 => NULL,
))
proxy::getErrorString returns ''
query...
errno...
proxy::getErrorString(array (
  0 => NULL,
))
proxy::getErrorString returns 'You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near \'WILL_I_EVER_LEARN_SQL?\' at line 1'
string(168) "You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'WILL_I_EVER_LEARN_SQL?' at line 1"
close...