On 2 September 2012 16:37, Glenn Fowler <g...@research.att.com> wrote: > > On Sun, 2 Sep 2012 12:43:58 +0200 Cedric Blancher wrote: >> On 2 September 2012 06:04, Glenn Fowler <g...@research.att.com> wrote: >> > >> > is there any rationale for there being no *at() variant for >> > >> > chdir() >> > truncate() > >> If I remember it right from the old POSIX conf calls: Everything which >> requires to access a file's content and has a f* function should go >> through openat()+f*(). In this case this means you'd have to call >> openat() to get a file handle and use ftruncate(). > >> chdir() has explicitly no at version because the same basic rule >> (replace "file's content" with "directory's content") applies: Use >> openat() with O_SEARCH+fchdir(). It's two syscalls but it's almost >> having identical performance. And you always have the directory fd >> around for later usage :) > > thanks > and I'll keep that "2 syscalls almost the same as 1" in my back pocket
No, no, I didn't mean that as general rule. Just the combination of openat() and fchdir() is fast because fchdir() has almost nothing todo except swapping some pointers. Ced -- Cedric Blancher <cedric.blanc...@googlemail.com> Institute Pasteur _______________________________________________ ast-developers mailing list ast-developers@research.att.com https://mailman.research.att.com/mailman/listinfo/ast-developers
