(PHP 4 >= 4.0.6, PHP 5)
fbsql_username — Get or set the username for the connection
Get or set the username used for the connection.
由 fbsql_connect() 或 fbsql_pconnect() 返回的 FrontBase 链接标识符.
如可选并未指定，函数会尝试查找一个到 FrontBase 服务器的开放链接，且如没有找到这样的链接，会尝试通过不带参数调用 fbsql_connect() 来创建一个。
If provided, this is the new username to set.
Returns the current username used with the connection, as a string.