DESCRIPTIONqueries all currently opened joysticks for position changes and calls the appropriate event handlers.
A non-zero value is returned if and only if any joystick reported a position change. In more detail the logical and of the return value and (1 << joydev) is non-zero if this joystick status changed.
CAVEATSThis function is only available in ELF versions of svgalib. Due to backwards compatibility issues it cannot be used with shared a.out libs.