On Wed, Jan 27, 2016 at 09:34:35PM +0000, Mathieu Desnoyers wrote: > ----- On Jan 27, 2016, at 12:37 PM, Thomas Gleixner [email protected] wrote: > > > On Wed, 27 Jan 2016, Thomas Gleixner wrote: > > > >> On Wed, 27 Jan 2016, Mathieu Desnoyers wrote: > >> > ----- On Jan 27, 2016, at 12:22 PM, Thomas Gleixner [email protected] > >> > wrote: > >> > Sounds fair. What is the recommended typing for "ptr" then ? > >> > uint32_t ** or uint32_t * ? > >> > > >> > It would be expected to pass a "uint32_t *" for the set > >> > operation, but the "get" operation requires a "uint32_t **". > >> > >> Well, you can't change the types depending on the opcode, so you need to > >> stick > >> with **. > > > > Alternatively you make it: > > > > (opcode, *newptr, **oldptr, flags); > > I'm tempted to stick to (opcode, **ptr, flags), because > other syscalls that have "*newptr", "**oldptr" > typically have them because they save the current state > into oldptr, and set the new state, which is really > not the case here. To eliminate any risk of confusion, > I am tempted to keep a single "**ptr". > > Unless someone has a better idea...
Either that or you could define it as "void *" and interpret it based on flags, but that seems unfortunate; let's not imitate ioctl-style typeless parameters. I'd stick with the double pointer and the current behavior.
