On Wed, Nov 16, 2011 at 01:14:28PM +0000, Alexander Best wrote: > On Wed Nov 16 11, Joerg Sonnenberger wrote: > > On Tue, Nov 15, 2011 at 08:24:50PM +0000, Alexander Best wrote: > > > one of the things i'm missing is an easy way to determine, whether a > > > stream or > > > fd is seekable. i checked the dd(1) and hd(1) sources and those tools are > > > performing so much stuff just to find out if this is the case, and they > > > still > > > are doing a very poor job. > > > > Isn't the primary issue that FreeBSD doesn't properly report errors for > > lseek(2)? I think you should start from that and not hack around the > > fallout... > > what do you mean? lseek(2) returns -1, when the file descriptor is not > seekable. i fired lseek(2) at all sorts of file types (dir, sockets, ...) > and it always returned the correct result.
If that were the case, you wouldn't need your flag to detect seek support. But e.g. some devices silently ignore seek requests without reporting errors. At least that is what I remember from the last time this has brought up. Joerg _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
