man: add man page for io_uring_peek_batch_cqe()

Link: #1263
Signed-off-by: Jens Axboe <[email protected]>

man/io_uring_peek_batch_cqe.3

@@ -0,0 +1 @@
+io_uring_peek_cqe.3

man/io_uring_peek_cqe.3

@@ -11,6 +11,10 @@ io_uring_peek_cqe \- check if an io_uring completion event is available
 .PP
 .BI "int io_uring_peek_cqe(struct io_uring *" ring ","
 .BI "                      struct io_uring_cqe **" cqe_ptr ");"
+.PP
+.BI "int io_uring_peek_batch_cqe(struct io_uring *" ring ","
+.BI "                            struct io_uring_cqe **" cqe_ptrs ","
+.BI "                            unsigned count ");"
 .fi
 .SH DESCRIPTION
 .PP
@@ -25,12 +29,27 @@ param is filled with a valid CQE entry.
 This function does not enter the kernel to wait for an event, an event
 is only returned if it's already available in the CQ ring.
 
+The
+.BR io_uring_peek_batch_cqe (3)
+function returns up to
+.I count
+request completions in
+.I cqe_ptrs
+belonging to the
+.I ring
+param, if they are readily available. It will not enter the kernel, unless the
+CQ ring is in an overflow condition. Upon succesful return,
+.I cqe_ptrs
+are filled with the number of events indicated by the return value.
+
 .SH RETURN VALUE
 On success
 .BR io_uring_peek_cqe (3)
 returns
 .B 0
-and the cqe_ptr parameter is filled in. On failure it returns
+and the cqe_ptr parameter is filled in. On success
+.BR io_uring_peek_batch_cqe (3)
+returns the number of completions filled in. On failure, they may return
 .BR -EAGAIN .
 .SH SEE ALSO
 .BR io_uring_submit (3),