Man page 3 : XkbChangeControls

XkbChangeControls - Provides a flexible method for updating the controls in a server to match those in the changed keyboard description

Bool XkbChangeControls (Display * dpy , XkbDescPtr xkb , XkbControlsChangesPtr changes );

• - dpy
      connection to X server
• - xkb
      keyboard description with changed xkb->ctrls
• - changes
      which parts of xkb->ctrls have changed

The XkbControlsChangesRec structure allows applications to track modifications to an XkbControlsRec structure and thereby reduce the amount of traffic sent to the server. The same XkbControlsChangesRec structure may be used in several successive modifications to the same XkbControlsRec structure, then subsequently used to cause all of the changes, and only the changes, to be propagated to the server. The changed_ctrlsfield is a mask specifying which logical sets of data in the controls structure have been modified. In this context, modified means set,that is, if a value is set to the same value it previously contained, it has still been modified, and is noted as changed. Valid values for changed_ctrlsare any combination of the masks listed in Table 1 that have "ok" in the changed_ctrlscolumn. Setting a bit implies the corresponding data fields from the "Relevant XkbControlsRec Data Fields" column in Table 1 have been modified. The enabled_ctrls_changesfield specifies which bits in the enabled_ctrlsfield have changed. If the number of keyboard groups has changed, the num_groups_changedfield is set to True. Table 1 shows the actual values for the individual mask bits used to select controls for modification and to enable and disable the control. Note that the same mask bit is used to specify general modifications to the parameters used to configure the control (which), and to enable and disable the control (enabled_ctrls). The anomalies in the table (no "ok" in column) are for controls that have no configurable attributes; and for controls that are not boolean controls and therefore cannot be enabled or disabled.

Table 2 shows the actual values for the individual mask bits used to select controls for modification and to enable and disable the control. Note that the same mask bit is used to specify general modifications to the parameters used to configure the control (which), and to enable and disable the control (enabled_ctrls). The anomalies in the table (no "ok" in column) are for controls that have no configurable attributes; and for controls that are not boolean controls and therefore cannot be enabled or disabled.

If you have an Xkb description with controls that have been modified and an XkbControlsChangesRec that describes the changes that have been made, the XkbChangeControlsfunction provides a flexible method for updating the controls in a server to match those in the changed keyboard description. XkbChangeControlscopies any controls fields specified by changesfrom the keyboard description controls structure, xkb->ctrls,to the server specified by dpy.

The XkbControlsChangesRec structure is defined as follows:

typedef struct _XkbControlsChanges {
    unsigned int  changed_ctrls;         /(** bits indicating changed control data
*/
    unsigned int  enabled_ctrls_changes; /(** bits indicating enabled/disabled
controls */
    Bool          num_groups_changed;    /(** True if number of keyboard groups
changed */
} XkbControlsChangesRec,*XkbControlsChangesPtr;