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From: saj@chinet.chi.il.us (Stephen Jacobs)
Newsgroups: comp.sys.atari.st
Subject: Re: Bug in TURBO-C V1.0
Summary: I don't like it, but K&R constants don't have signs
Message-ID: <1990Feb16.150818.18727@chinet.chi.il.us>
Date: 16 Feb 90 15:08:18 GMT
References: <8910270333.AA14741@cscwam.UMD.EDU> <0927891128429423@thelake.UUCP> <1990Feb14.173746.28244@agate.berkeley.edu> <1302@lzsc.ATT.COM>
Reply-To: saj@chinet.chi.il.us (Stephen Jacobs)
Organization: Chinet - Chicago Public Access UNIX
Lines: 13

My two cents on the behavior of the 'constant' -32768 in C.  If something is
#define ed as -32768, remember that that means a _textual_ substitution will
be made wherever that thing appears (in contrast to a numeric substitution).
So the normal rules for integer constants apply (rather than some special
rule that might apply to preprocessor actions: the preprocessor action is
simple).  Integer constants don't have leading signs.  -32768 gives the
result of applying unary minus to the integer constant 32768.  And on a 16
bit model compiler, there isn't an integer 32768.  So the value of -32768 is
free to vary depending on context.  One hopes a warning message is generated
(it is in Mark Williams C).  Frankly, -32768 is such a convenient value for
flags on a 2-s complement machine, that I'd like integer constants to have
an optional leading sign, but it isn't defined that way.
                                  Steve J.