XChangePointerControl(display, do_accel, do_threshold, accel_numerator, 
                        accel_denominator, threshold)
      Display *display;
      Bool do_accel, do_threshold;
      int accel_numerator, accel_denominator;
      int threshold;


display Specifies the connection to the X server.
do_accel Specifies a Boolean value that controls whether the values for the accel_numerator or accel_denominator are used.
do_threshold Specifies a Boolean value that controls whether the value for the threshold is used.
accel_numerator Specifies the numerator for the acceleration multiplier.
accel_denominator Specifies the denominator for the acceleration multiplier.
threshold Specifies the acceleration threshold.


The XChangePointerControl() function defines how the pointing device moves. The acceleration, expressed as a fraction, is a multiplier for movement. For example, specifying 3/1 means the pointer moves three times as fast as normal. The fraction may be rounded arbitrarily by the X server. Acceleration only takes effect if the pointer moves more than threshold pixels at once and only applies to the amount beyond the value in the threshold argument. Setting a value to \-1 restores the default. The values of the do_accel and do_threshold arguments must be True for the pointer values to be set, or the parameters are unchanged. Negative values (other than \-1) generate a BadValue error, as does a zero value for the accel_denominator argument.

XChangePointerControl() can generate a BadValue error.


BadValue Some numeric value falls outside the range of values accepted by the request. Unless a specific range is specified for an argument, the full range defined by the argument's type is accepted. Any argument defined as a set of alternatives can generate this error.

See also

XGetPointerControl(), "Keyboard and Pointer Settings".
Christophe Tronche, ch@tronche.com