hotplug: Document that callbacks cannot unregister themselves when called from hotplug_register_callback

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/libusb/hotplug.c b/libusb/hotplug.c
index 16725f2..2465f6e 100644
--- a/libusb/hotplug.c
+++ b/libusb/hotplug.c
@@ -59,7 +59,11 @@
  *
  * A callback function must return an int (0 or 1) indicating whether the callback is
  * expecting additional events. Returning 0 will rearm the callback and 1 will cause
- * the callback to be deregistered.
+ * the callback to be deregistered. Note that when callbacks are called from
+ * libusb_hotplug_register_callback() because of the \ref LIBUSB_HOTPLUG_ENUMERATE
+ * flag, the callback return value is ignored, iow you cannot cause a callback
+ * to be deregistered by returning 1 when it is called from
+ * libusb_hotplug_register_callback().
  *
  * Callbacks for a particular context are automatically deregistered by libusb_exit().
  *