On Fri, Jul 24, 2009 at 11:32:59PM +0200, Matthias Kilian wrote:
> The portable way would be to enlarge the buffer and retry whenever
> you get ERANGE. I ran into this problem several weeks ago for GHC
> (and a diff doing the try/enlarge/retry-game had been accepted
> upstream). IIRC, there even was some #ifdef'ing around that already
> increased the buffer especially for OpenBSD,
To clarify, read: increased the *statically sized buffer* especially
for OpenBSD.
>From libraries/unix/System/Posix/Unix.hsc (as in ghc-6.10):
#if defined(HAVE_SYSCONF) && defined(HAVE_SC_GETGR_R_SIZE_MAX)
grBufSize = sysconfWithDefault 2048 (#const _SC_GETGR_R_SIZE_MAX)
#else
grBufSize = 2048 -- just assume some value (1024 is too small on
OpenBSD)
#endif
Anyway, on an OS without any limit on possible group members, no
constant value nor any value returned by sysconf(3) is guaranteed
to be large enough for getgrnam_r(3).
Ciao,
Kili
