There are several ways of checking if the device is advertising:
Most of the examples in the SDK will indicate advertising by blinking LED 1 (BSP_INIDCATE_ADVERTISING). However, this may vary and you have to check with the specific application.
Download nRF Connect on the phone, and check if you see the device advertising with the name set in the application flashed onto the chip (through sd_ble_gap_device_name_set(..) )
Check if the return value of sd_ble_gap_adv_start(..) is NRF_SUCCESS (=0x00)
But I meant to a software indication (flag, state etc...). I need an indication so I will not start advertising twice. I tried to manage my own flag, but it cause a lot of problems.
What problems do you face when using your own flags? Race conditions? If that is the case, I think this thread is a good read, and Ulrich presents a good solution to handle it.
