Why is the whitelist set to NULL?

[Andrew]

I am looking at the ble_app_hrs_c example (with the s130 soft device on pca10028 dev board). I have set the m_scan_mode to BLE_WHITELIST_SCAN to enable whitelisting. In the "on_ble_eve" function just before it connects, it sets the "p_whitelist" variable to NULL. The description of that variable in the documentation says:

"Pointer to whitelist, NULL if no whitelist or the current active whitelist is to be used."

And the documentation for the fuction "sd_ble_gap_connect" says:

"To use the currently active whitelist set p_scan_params->p_whitelist to NULL."

I see that to use whitelisting you need to set this to NULL. Wouldn't you want it always pointing to a whitelist if you are trying to use a whitelist? How is setting that pointer to NULL useful?

[tesc]

Hi,

p_whitelist is set to NULL in one of the two possible cases. This is to allow the ble_app_hrs_c example to connect to new devices. In the other case it is set to point to a whitelist.

The reason why there is a non-whitelist case is to allow the device to connect to new peripherals. These peripherals can then be added to the whitelist. In this example the Device Manager is used for building a whitelist of all of the bonded devices, using dm_whitelist_create(). If there are no bonded devices the whitelist will be empty, resulting in using the NULL pointer and not using whitelist, allowing for a new device to bond.

If you do have another way to build the whitelist you can manage with only the case using the whitelist.

Regards, Terje

[tesc]

Sorry for the many updates, I had a deeper look into things.

The example is using the Device Manager function dm_whitelist_create() to generate a whitelist consisting of all the currently bonded devices. If there are no bonded devices it will use the empty whitelist.