diff options
Diffstat (limited to 'libusb/libusb.h')
| -rw-r--r-- | libusb/libusb.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/libusb/libusb.h b/libusb/libusb.h index 875b6f1..97aeecc 100644 --- a/libusb/libusb.h +++ b/libusb/libusb.h @@ -1897,6 +1897,18 @@ typedef int (LIBUSB_CALL *libusb_hotplug_callback_fn)(libusb_context *ctx, * armed until either it is deregistered with libusb_hotplug_deregister_callback() * or the supplied callback returns 1 to indicate it is finished processing events. * + * If the \ref LIBUSB_HOTPLUG_ENUMERATE is passed the callback will be + * called with a \ref LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED for all devices + * already plugged into the machine. Note that libusbx modifies its internal + * device list from a separate thread, while calling hotplug callbacks from + * libusb_handle_events(), so it is possible for a device to already be present + * on, or removed from, its internal device list, while the hotplug callbacks + * still need to be dispatched. This means that when using \ref + * LIBUSB_HOTPLUG_ENUMERATE, your callback may be called twice for the arrival + * of the same device, once from libusb_hotplug_register_callback() and once + * from libusb_handle_events(); and/or your callback may be called for the + * removal of a device for which an arrived call was never made. + * * Since version 1.0.16, \ref LIBUSBX_API_VERSION >= 0x01000102 * * \param[in] ctx context to register this callback with |