Checks whether the connection to the server is working. If the connection has gone down and auto-reconnect is enabled an attempt to reconnect is made. If the connection is down and auto-reconnect is disabled, mysql_ping() returns an error.

Auto-reconnect is disabled by default. To enable it, call mysql_options() with the MYSQL_OPT_RECONNECT option. For details, see Section 7.49, “mysql_options()”.

mysql_ping() can be used by clients that remain idle for a long while, to check whether the server has closed the connection and reconnect if necessary.

If mysql_ping()) does cause a reconnect, there is no explicit indication of it. To determine whether a reconnect occurs, call mysql_thread_id() to get the original connection identifier before calling mysql_ping(), then call mysql_thread_id() again to see whether the identifier has changed.

If reconnect occurs, some characteristics of the connection will have been reset. For details about these characteristics, see Chapter 20, C API Automatic Reconnection Control.

Zero if the connection to the server is active. Nonzero if an error occurred. A nonzero return does not indicate whether the MySQL server itself is down; the connection might be broken for other reasons such as network problems.