C++: Hot to determine current startup volume/device on Mac

I want to determine the current startup volume on a Mac from a plugin I am coding. So far, I am able to determine a list of volumes (statfs) with its values => f_mntfromname char [1024] "/dev/disk1s1" etc.

Unfortunately this list includes MNT_BOOTFS drives, that are basically backup volumes or crypto-volumes, with the same mounting points.

What I need to know is, what volume is the startup drive or the volume the OS is currently running on.

Can you guys please help? Thanks