a couple of random questions (lseek)
Henry Spencer
henry at utzoo.uucp
Fri Apr 15 12:19:37 AEST 1988
> Second, what is the portable way to rewind a Unix file
> descriptor? On almost every machine I have ever used:
>
> lseek(fd, (off_t)0, SEEK_SET);
>
> works because the offset is a byte count, but it is inevitable
> that on some machine, off_t is the pointer to some kind of
> struct, or at least is *not* simply a byte count...
Not on a *Unix* machine. There is no portable way to rewind a Unix
file descriptor, because Unix file descriptors are not portable!
On a Unix system, (off_t)0 is fine. On a seriously non-Unix system,
you have to use stdio streams instead, in which case rewind() is
available. For vaguely Unix-like systems, all bets are off.
--
"Noalias must go. This is | Henry Spencer @ U of Toronto Zoology
non-negotiable." --DMR | {allegra,ihnp4,decvax,utai}!utzoo!henry
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