h6. [[FilterManager]] h6(. » [[FilterManager SWI Calls|SWI Calls]] h6((. » Filter_RegisterPostFilter h2. Filter_RegisterPostFilter h5. (SWI &42641) |_<^{width:4em}. Entry | | |<^. R0 |<^. Pointer to zero terminated filter name| |<^. R1 |<^. Address of [[Post Filter Code]]| |<^. R2 |<^. Value to be passed to R12 | |<^. R3 |<^. Task handle of task to which filter is applied, or 0 for all tasks | |<^. R4 |<^. [[Poll Mask]] (value of 1 masks the event – same as [[Wimp_Poll]]) | |_<^. Exit | |<. All registers preserved| h4. Use The purpose of this call is to add a new filter to the list of post-filters. h4. Notes The filter routine at the address pointed to by R1 will be called whenever the Wimp is about to return from [[Wimp_Poll]]. When registering the filter use R3 to control whether the filter is called for all tasks or only for a specific task. See [[Post Filter Code]] for details of how the filter routine must operate. h4. See also * [[Filter_DeRegisterPostFilter]] * [[Filter_DeRegisterPreFilter]] * [[Filter_RegisterPreFilter]] * [[Poll Mask]]