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NOTE: This API is deprecated from FreeRTOS V4.0.0 onwards. Please refer to xApplicationDNSQueryHook_Multi for the new API supporting IPv6, Multiple Endpoints and Multiple interfaces. To use this deprecated API please set ipconfigIPv4_BACKWARD_COMPATIBLE to 1 in the FreeRTOSIPConfig.h header file.


[FreeRTOS-Plus-TCP API Reference]


Note: this hook needs to be defined only when ipconfigUSE_NBNS or ipconfigUSE_LLMNR is set to 1 in the FreeRTOSIPConfig.h file.

BaseType_t xApplicationDNSQueryHook( const char * pcName );

xApplicationDNSQueryHook is an application defined hook (or callback) function that is called by the FreeRTOS-Plus-TCP stack to check whether the LLMNR or NBNS name received is the same as the one device is looking for.

Callback functions are implemented by the application writer, but called by the TCP/IP stack. The prototype of the callback function must exactly match the prototype above (including the function name). The code in an application hook should not call FreeRTOS-Plus-TCP API's that are blocking. That could easily lead to a dead-lock.

When an application hook executes, it borrows the task priority and the stack of the IP-task. Therefore, we recommend that you keep application hooks short--it may want to wakeup some application task which will do further processing.



The name received by the TCP/IP stack.

Return value:

If the value in pcName matches the name of the device, then pdTRUE should be returned by the hook. Otherwise, a pdFALSE should be returned.

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