XkbSASetPtrDfltValue - Man Page

void XkbSASetPtrDfltValue (XkbAction act, int val);

act

action in which to set valueXXX

val

value to set in valueXXX

Actions associated with the XkbPtrDfltAction structure change the mk_dflt_btn  attribute of the MouseKeys control.

If the MouseKeys control is not enabled, KeyPress and KeyRelease events are  treated as though the action is XkbSA_NoAction. Otherwise, this action changes  the mk_dflt_btn attribute of the MouseKeys control.

The type field of the XkbPtrDfltAction structure should always be XkbSA_SetPtrDflt.

The flags field is composed of the bitwise inclusive OR of the values shown in Table 1  (currently there is only one value defined).

The affect field specifies what changes as a result of this action. The only valid value  for the affect field is XkbSA_AffectDfltBtn.

The valueXXX field is a signed character that represents the new button value for the mk_dflt_btn attribute of the MouseKeys control. If XkbSA_DfltBtnAbsolute is set in flags, valueXXX specifies the button to be used; otherwise, valueXXX specifies the amount to be added to the current default button. In either case,  illegal button choices are wrapped back around into range. Xkb provides macros,  to convert between the integer and signed character values in XkbPtrDfltAction  structures.

    typedef struct _XkbPtrDfltAction {
        unsigned char    type;      /* XkbSA_SetPtrDflt */
        unsigned char    flags;     /* controls the pointer button number */
        unsigned char    affect;    /* XkbSA_AffectDfltBtn */
        char             valueXXX;  /* new default button member */
    } XkbPtrDfltAction;