h6. [[OS SWI Calls]] h6(. » OS_Pointer h2. OS_Pointer h5. (SWI &64) |_<^{width:4em}. Entry | | |<^. R0 |<^. "Reason code":#reason| |\2<^. All other registers are dependent on reason code| |_<^{width:4em}. Exit | | |\2<^. Registers dependent on reason code| h4. Use The purpose of this call is to perform a pointer(mouse) operation. h4. Notes The action performed depends on the reason code value in R0. Many versions of RISC OS contain a bug which will cause OS_Pointer to malfunction or crash if called with an unsupported reason code. Therefore, care must be taken when attempting to make use of reason codes 2 and above. Internally this call makes use of the [[PointerV]] software vector to communicate with the pointer driver(s). h4(#reason). Reason Codes |_<^{width:4em}. #|_<^{width:4em}. Hex #|_<^. Action| |<^. 0|<^. &00|<^. [[OS_Pointer 0|Get pointer type]]| |<^. 1|<^. &01|<^. [[OS_Pointer 1|Set pointer type]]| |/2<^. 2|/2<^. &02|<^. [[OS_Pointer 2|Read alternate position]] (desktop RISC OS)| |<^. Read pointer presence (NCOS only)| h4. See also * [[PointerV]] * [[OS_Mouse]]