sd_app_evt_wait() returns error code 2

Question

I've cut the BLE proximity app example code back to doing nothing more than this: 
 int main(void)
{
 uint32_t err_code;
 
 leds_init();

 for (;;)
 {
 power_manage();
 }
}
 
 LED 7 (ASSERT_LED_PIN_NO) is on straight away. Debugging power_manage(), I see the error code returned by sd_app_evt_wait() is 2. What does this mean? There's nothing in the docs for sd_app_evt_wait() to explain anything but NRF_SUCCESS as a return value.

Ole Morten · Accepted Answer

You should refer to nrf_error.h for information on the error codes. There, you can see that 0x02 means NRF_ERROR_SOFTDEVICE_NOT_ENABLED. 
 All softdevice function calls (identified by their sd_* prefix) requires the softdevice to be enabled.