On Thu, Mar 02, 2006, Rainer.scherg wrote: > Johannes Stezenbach schrieb: > >1. ioctl(FE_GET_VERSION); > > if (api_version_minor > 1) > > /* assume FE_SET_STANDARD is available */ > > > >2. ioctl(FE_GET_CAPS); > > if (caps & FE_CAP_SET_STANDARD) > > /* we know FE_SET_STANDARD is available */ > > > >My personal preference is 2. > > "2." will work as long as there is no need to change > any data structures. Best example here is the switch from > DVB API v1 to v3. v1 API was considered unstable/beta, i.e. is was deemed acceptable to make incompatible changes. VDR was about the only user at the time, so while it wasn't nice for the vdr guys to deal with, I think it was the right decision. > Enabling an application to check the api version at runtime > has 3 advantages: > - application can do stop smoothly before crashing due > to wrong data structures That must never happen. We guarantee backwards compatibility, even at the expense that the API gets uglier. > - application can do a fallback They can do it without GET_VERSION. > - no effort to implement (no one gets hurt here) Simple to implement in dvb-core, hard for all application and library authors to deal with. They are the ones who get hurt. > Also a word about what we discussed on IRC: > > IMO we should take the chan[g|c]e to design a new dvb api here > e.g. "skip" v4 and start v4.1 or v5). > > A "frozen" api v3 compatibility layer should be provided for > the new api, so older/current applications can be run without > redesign or code changes. > > The new api doesn't need to follow api v3 (or v4) structures > (e.g. better use pointers instead of unions in some data > structures to get more flexibility to enhancements, etc.). Sounds good ;-), but is independent of the current task of adding DVB-S2 support with as little fuss as possible. Johannes _______________________________________________ linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
