7.4.1 mysql_fetch_row_nonblocking()

enum net_async_status
mysql_fetch_row_nonblocking(MYSQL_RES *result,
                            MYSQL_ROW *row)

Description

Note

mysql_fetch_row_nonblocking() is an asynchronous function. It is the counterpart of the mysql_fetch_row() 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_fetch_row_nonblocking() is used similarly to mysql_fetch_row(). For details about the latter, see Section 5.4.22, “mysql_fetch_row()”. The two functions differ as follows:

• mysql_fetch_row() returns a MYSQL_ROW value containing the next row, or NULL. The meaning of a NULL return depends on which function was called preceding mysql_fetch_row():

  • When used after mysql_store_result() or mysql_store_result_nonblocking(), mysql_fetch_row() returns NULL if there are no more rows to retrieve.

  • When used after mysql_use_result(), mysql_fetch_row() returns NULL if there are no more rows to retrieve or an error occurred.

• mysql_fetch_row_nonblocking() returns an enum net_async_status status indicator and takes a second row argument that provides a pointer to a MYSQL_ROW value. When the return status is NET_ASYNC_COMPLETE, the row argument is a pointer to a MYSQL_ROW value containing the next row, or NULL. The meaning of NULL depends on which function was called preceding mysql_fetch_row_nonblocking():

  • When used after mysql_store_result() or mysql_store_result_nonblocking(), the row argument is NULL if there are no more rows to retrieve.

  • When used after mysql_use_result(), the row argument is NULL if there are no more rows to retrieve or an error occurred.

mysql_fetch_row_nonblocking() was added in MySQL 8.0.16.

Return Values

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.

Example

See Chapter 7, C API Asynchronous Interface.