Constant xcb::ffi::xproto::XCB_ALLOW_SYNC_KEYBOARD

pub const XCB_ALLOW_SYNC_KEYBOARD: xcb_allow_t = 0x04;

For SyncKeyboard, if the keyboard is frozen and actively grabbed by the client, keyboard event processing continues normally until the next KeyPress or KeyRelease event is reported to the client, at which time the keyboard again appears to freeze. However, if the reported event causes the keyboard grab to be released, then the keyboard does not freeze. SyncKeyboard has no effect if the keyboard is not frozen by the client or if the keyboard is not grabbed by the client.