DOKK / manpages / debian 10 / libx11-doc / XkbLatchModifiers.3.en
XkbLatchModifiers(3) XKB FUNCTIONS XkbLatchModifiers(3)

XkbLatchModifiers - Latches and unlatches any of the eight real keyboard modifiers

Bool XkbLatchModifiers (Display *display, unsigned int device_spec, unsigned int affect, unsigned int values);

connection to the X server
device ID, or XkbUseCoreKbd
mask of real modifiers whose lock state is to change
1 => lock, 0 => unlock; only for modifiers selected by affect

XkbLatchModifiers sends a request to the server to latch the real modifiers selected by both affect and values and to unlatch the real modifiers selected by affect , but not selected by values.

XkbLatchModifiers does not wait for a reply from the server. It returns True if the request was sent, and False otherwise.

The functions in this section that change the use of modifiers use a mask in the parameter affect. It is a bitwise inclusive OR of the legal modifier masks:

Table 1 Real Modifier Masks
Mask
ShiftMask
LockMask
ControlMask
Mod1Mask
Mod2Mask
Mod3Mask
Mod4Mask
Mod5Mask

The XkbLatchModifiers function returns True if a request was sent to the server to latch the real modifiers selected by both affect and values and to unlatch the real modifiers selected by affect , but not selected by values.
The XkbLatchModifiers function returns False if the request was not sent.

libX11 1.6.7 X Version 11