enum net_async_status
mysql_real_connect_nonblocking(MYSQL *mysql,
                               const char *host,
                               const char *user,
                               const char *passwd,
                               const char *db,
                               unsigned int port,
                               const char *unix_socket,
                               unsigned long
                               client_flag)
            mysql_real_connect_nonblocking()
            is an asynchronous function. It is the counterpart of the
            mysql_real_connect()
            synchronous function, for use by applications that require
            asynchronous communication with the server. For general
            information about writing asynchronous C API applications,
            see Chapter 7, C API Asynchronous Interface.
          
          mysql_real_connect_nonblocking()
          is used similarly to
          mysql_real_connect(). For
          details about the latter, see
          Section 5.4.58, “mysql_real_connect()”. The two functions differ
          as follows:
        
- mysql_real_connect()returns a connection handler or- NULL.
- mysql_real_connect_nonblocking()returns an- enum net_async_statusstatus indicator.
          mysql_real_connect_nonblocking()
          was added in MySQL 8.0.16.
        
          Returns an enum net_async_status value. See
          the description in
          Section 7.2, “C API Asynchronous Interface Data Structures”. A
          NET_ASYNC_ERROR return status indicates an
          error.