nbd_aio_peek_command_completed - check if any command has completed
#include <libnbd.h> int64_t nbd_aio_peek_command_completed (struct nbd_handle *h);
Return the unique positive 64 bit cookie of the first non-retired but completed command,
0 if there are in-flight commands but none of them are awaiting retirement, or
-1 on error including when there are no in-flight commands. Any cookie returned by this function must still be passed to nbd_aio_command_completed(3) to actually retire the command and learn whether the command was successful.
This call returns a 64 bit signed integer ≥
-1 is returned.
Refer to "ERROR HANDLING" in libnbd(3) for how to get further details of the error.
This function first appeared in libnbd 1.0.
If you need to test if this function is available at compile time check if the following macro is defined:
#define LIBNBD_HAVE_NBD_AIO_PEEK_COMMAND_COMPLETED 1
nbd_aio_command_completed(3), nbd_create(3), libnbd(3).
Richard W.M. Jones
Copyright (C) 2019-2021 Red Hat Inc.
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