QSA provides some basic synchronization capabilities.
An application can find out where in the stream the hardware capture position is. The resolution of this position is entirely a function of the hardware driver; consult the specific device driver documentation for details if this is important to your application.
The API calls to get this information are:
Both of these functions fill in a snd_pcm_channel_status_t structure. You'll need to check the following members of this structure: