MySQL 5.7 C API Developer Guide
int
mysql_refresh(MYSQL *mysql,
              unsigned int options)
            As of MySQL 5.7.11, mysql_refresh() is
            deprecated and is subject to removal in a future version of
            MySQL. Instead, use
            mysql_query() or
            mysql_real_query() to
            execute a FLUSH statement.
          
          This function flushes tables or caches, or resets replication
          server information. The connected user must have the
          RELOAD privilege.
        
          The options argument is a bitmask composed
          from any combination of the following values. Multiple values
          can be OR'ed together to perform multiple operations with a
          single call.
        
              REFRESH_GRANT
            
              Refresh the grant tables, like FLUSH
              PRIVILEGES.
            
              REFRESH_LOG
            
              Flush the logs, like FLUSH
              LOGS.
            
              REFRESH_TABLES
            
              Flush the table cache, like FLUSH
              TABLES.
            
              REFRESH_HOSTS
            
              Flush the host cache, like FLUSH
              HOSTS.
            
              REFRESH_STATUS
            
              Reset status variables, like FLUSH
              STATUS.
            
              REFRESH_THREADS
            
Flush the thread cache.
              REFRESH_SLAVE
            
              On a replica server, reset the source server information
              and restart the replica, like RESET
              SLAVE.
            
              REFRESH_MASTER
            
              On a source server, remove the binary log files listed in
              the binary log index and truncate the index file, like
              RESET MASTER.
            
Commands were executed in an improper order.
The MySQL server has gone away.
The connection to the server was lost during the query.
An unknown error occurred.