(PHP 4 >= 4.0.1, PECL yaz:0.9-1.0.9)
yaz_addinfo — Returns additional error information
Returns additional error information for the last request on the server.
With some servers, this function may return the same string as yaz_error().
A string containing additional error information or an empty string if the last operation was successful or if no additional information was provided by the server.