Leaving this comment for records.
Even if you do not explicitly call the bind () function, windows binds the local port dynamically as described in MSDN, so you can find the information in the UDP extended table.
ref: https://docs.microsoft.com/en-us/windows/win32/api/winsock/nf-winsock-sendto
In previous tests, it was a simple coding mistake that we could not get a PID.
thanks for your help, Vadim Smirnov 🙂