io_uring_buf_ring_available - return number of unconsumed provided ring buffer entries

       The io_uring_buf_ring_available(3) helper returns the number of unconsumed (by the kernel) entries in the
       br provided buffer group belonging to the io_uring ring and identified by the buffer group ID bgid.

       Since  the  head  of the provided buffer ring is only visible to the kernel, it's impossible to otherwise
       know how many unconsumed entries exist in the given provided buffer ring. This function query the  kernel
       to return that number.  Available since kernel 6.8.

       io_uring_buf_ring_available - return number of unconsumed provided ring buffer entries

       The  returned number of entries reflect the amount of unconsumed entries at the time that it was queried.
       If inflight IO exists that may consume provided buffers from this buffer group, then the  returned  value
       is inherently racy.

       Returns the number of unconsumed entries on success, which may be 0. In case of error, may return -ENOENT
       if the specified buffer group doesn't exist, or -EINVAL if the buffer group isn't of the correct type, or
       if the kernel doesn't support this feature.

io_uring_register_buf_ring(3), io_uring_buf_ring_add(3), io_uring_buf_ring_cq_advance(3)

liburing-2.6                                      Jan 11, 2024                    io_uring_buf_ring_available(3)

#include<liburing.h>intio_uring_buf_ring_available(structio_uring*ring,structio_uring_buf_ring*br,unsignedshortbgid);