Table of Contents

## Name

XChangePointerControl, XGetPointerControl - control pointer

## Syntax

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;

XGetPointerControl(display, accel_numerator_return, accel_denominator_return,
threshold_return)
Display *display;
int *accel_numerator_return, *accel_denominator_return;
int *threshold_return;

## Arguments

accel_denominator
  Specifies the denominator for the acceleration multiplier.
accel_denominator_return
  Returns the denominator for the acceleration multiplier.
accel_numerator
  Specifies the numerator for the acceleration multiplier.
accel_numerator_return
  Returns the numerator for the acceleration multiplier.
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.
threshold
  Specifies the acceleration threshold.
threshold_return
  Returns the acceleration threshold.

## Description

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.

The XGetPointerControl function returns the pointer's current acceleration multiplier and acceleration threshold.

## Diagnostics

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

Xlib - C Language X Interface

Table of Contents

- Name
- Syntax
- Arguments
- Description
- Diagnostics
- See Also