调用mysql_select_db的返回值总是false

[yingge2016]

centos7

	if(!mysql_select_db(mysqlSt,db_name))
	{
		perror("mysql_select_db error.");
		mysql_error(mysqlSt);
		return;
	}

数据库已经连接。
输出是：
mysql_select_db error.: Success

[昵称很不好取]

返回0是表示连接正确吧 mysql_select_db() fails unless the connected user can be authenticated as having permission to use the database. Return Values Zero for success. Nonzero if an error occurred. Errors CR_COMMANDS_OUT_OF_SYNC Commands were executed in an improper order. CR_SERVER_GONE_ERROR The MySQL server has gone away. CR_SERVER_LOST The connection to the server was lost during the query. CR_UNKNOWN_ERROR An unknown error occurred.