Manual Reference Pages  - XChangePointerControl (3)


XChangePointerControl, XGetPointerControl - control pointer




int XChangePointerControl(Display *display, Bool do_accel, Bool do_threshold, int accel_numerator, int accel_denominator, int threshold);
int XGetPointerControl(Display *display, int *accel_numerator_return, int *accel_denominator_return, int *threshold_return);


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.


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.


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.


Xlib - C Language X Interface

X Version 11 XChangePointerControl (3) libX11 1.5.0
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