ble_gatts_clt_cfg_access_locked() function
Performs a read or write access on a client characteritic configuration descriptor (CCCD).
Arguments
conn
The connection of the peer doing the accessing. @apram attr_handle The handle of the CCCD.
att_op
The ATT operation being performed (read or write).
out_cccd
If the CCCD should be persisted as a result of the access, the data-to-be-persisted gets written here. If no persistence is necessary, out_cccd->chr_val_handle is set to 0.
Return value
0 on success; nonzero on failure.