Describes the type of connection in use for the connection, including the
server host name.
The MySQL connection. If the
link identifier is not specified, the last link opened by
mysql_connect() is assumed. If no such link is found, it
will try to create one as if mysql_connect() was called
with no arguments. If by chance no connection is found or established, an
E_WARNING level warning is generated.
Returns a string describing the type of MySQL connection in use for the
connection or FALSE on failure.