On Linux, I'm using hostapd in AP mode. In other words, the system is the hotspot.
I would like to know what is the frequency of the Wi-Fi via c code (or a bash script that I could translate to c code).
The following code which queries the kernel, only works in normal mode. It fails in AP mode.
ioctl(net_sock, SIOCGIWFREQ, &wrq);
In bash, I have tried:
iwconfig
iw dev
but it doesn't report the frequency of the Wi-Fi. Same problem: it only reports in normal mode when the system associates to a router but nothing in AP mode.
How can I query hostapd to know the frequency hostapd is using or is configured to use?