[TUHS] v7 K&R C

[Peter Pentchev]

On Sat, May 16, 2020 at 11:39:54AM -0600, Warner Losh wrote:
> On Sat, May 16, 2020 at 10:28 AM Paul Winalski <paul.winalski at gmail.com>
> wrote:
> 
> > > On Fri, May 15, 2020 at 4:02 PM <ron at ronnatalie.com> wrote:
> > >
> > >Unfortunately, if c is char on a machine with unsigned chars, or it’s of
> > >type unsigned char, the EOF will never be detected.
> > >
> > >    - while ((c = getchar()) != EOF) if (c == '\n') { /* entire record is
> > now there */
> >
> > The function prototype for getchar() is:    int getchar(void);
> >
> > It returns an int, not a char.  In all likelihood this is specifically
> > *because* EOF is defined as -1.  The above code works fine if c is an
> > int.  One always has to be very careful when doing a typecast of a
> > function return value.
> >
> 
> In the early days of my involvement with FreeBSD, I went through and fixed
> about a dozen cases where getopt was being assigned to a char and then
> compared with EOF. I'm certain that this is why. Also EOF has to be a value
> that's not representable by a character, or your 0xff bytes would disappear.

I think I remember a code review on one of my patches to du(1), I think,
something about adding an option to ignore specific names when
recursing, and I remember either you or BDE chastising me about
while (ch = getopt(...), ch != EOF) :)

G'luck,
Peter

-- 
Peter Pentchev  roam at ringlet.net roam at debian.org pp at storpool.com
PGP key:        http://people.FreeBSD.org/~roam/roam.key.asc
Key fingerprint 2EE7 A7A5 17FC 124C F115  C354 651E EFB0 2527 DF13
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: not available
URL: <http://minnie.tuhs.org/pipermail/tuhs/attachments/20200519/00625b9f/attachment.sig>