* Aleksa Sarai: > This is something that I've been thinking about for a while. We had a > discussion at LPC 2020 about this[1] but the proposals suggested there > never materialised. > > In short, it is quite difficult for userspace to detect the feature > capability of syscalls at runtime. This is something a lot of programs > want to do, but they are forced to create elaborate scenarios to try to > figure out if a feature is supported without causing damage to the > system. For the vast majority of cases, each individual feature also > needs to be tested individually (because syscall results are > all-or-nothing), so testing even a single syscall's feature set can > easily inflate the startup time of programs. > > This patchset implements the fairly minimal design I proposed in this > talk[2] and in some old LKML threads (though I can't find the exact > references ATM). The general flow looks like: By the way, I have recently tried to document things from a glibc perspective (which is a bit broader because we also have purely userspace types): [PATCH RFC] manual: Document how types change <https://inbox.sourceware.org/libc-alpha/8734m4n1ij.fsf@xxxxxxxxxxxxxxxxxxxxxxxxx/> (This patch has not yet been reviewed.)
