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From: guy%gorodish@Sun.COM (Guy Harris)
Newsgroups: comp.lang.c
Subject: Re: Writing readable code
Message-ID: <22635@sun.uucp>
Date: Thu, 2-Jul-87 21:11:36 EDT
Article-I.D.: sun.22635
Posted: Thu Jul  2 21:11:36 1987
Date-Received: Sat, 4-Jul-87 10:12:54 EDT
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> The assignment into a character causes getchar's int return
> to be changed to char, invalidating the following comparison  The
> effect is that characters of value 0xFF will cause erroneous end of
> file indication.  This is a common error in C, but it is fortunate
> that most text this is used on never contains any characters with the
> most significant bit set.

On a machine where "char" is not signed, this won't work even if you
run it on text consisting entirely of 7-bit characters.  "getchar"
will return EOF when it hits end-of-file; EOF (-1) will get converted
to '\377' (we assume 8-bit characters here; translate as needed for
other character sizes) which compares equal to 255 but not to -1.
Thus, you'll never see the end-of-file indication.
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy@sun.com