From d29a8a1b0758a905b148929dd14b79bfeb297a80 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Sat, 2 Jun 2018 09:52:59 +0100 Subject: [PATCH] main-loop: document IOCanReadHandler MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Signed-off-by: Stefan Hajnoczi Message-Id: <20180602085259.17853-1-stefanha@redhat.com> Signed-off-by: Paolo Bonzini Reviewed-by: Philippe Mathieu-Daudé --- include/qemu/main-loop.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/include/qemu/main-loop.h b/include/qemu/main-loop.h index 6b4b60bf6d..721aa2416a 100644 --- a/include/qemu/main-loop.h +++ b/include/qemu/main-loop.h @@ -168,6 +168,20 @@ void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque); /* async I/O support */ typedef void IOReadHandler(void *opaque, const uint8_t *buf, int size); + +/** + * IOCanReadHandler: Return the number of bytes that #IOReadHandler can accept + * + * This function reports how many bytes #IOReadHandler is prepared to accept. + * #IOReadHandler may be invoked with up to this number of bytes. If this + * function returns 0 then #IOReadHandler is not invoked. + * + * This function is typically called from an event loop. If the number of + * bytes changes outside the event loop (e.g. because a vcpu thread drained the + * buffer), then it is necessary to kick the event loop so that this function + * is called again. aio_notify() or qemu_notify_event() can be used to kick + * the event loop. + */ typedef int IOCanReadHandler(void *opaque); /** -- 2.11.0