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- Path: sdrc.com!thor!scjones
- From: larry.jones@sdrc.com (Larry Jones)
- Newsgroups: comp.std.c
- Subject: Re: Undefined result vs. int's holding undefined values.
- Date: 9 Jan 1996 19:58:54 GMT
- Organization: SDRC Engineering Services
- Distribution: world
- Message-ID: <4cuhdu$ff2@info1.sdrc.com>
- References: <4ck70b$rd7@news.informix.com> <4ckms5$rd7@news.informix.com> <4cpv1n$apm@der.twinsun.com>
- NNTP-Posting-Host: thor.sdrc.com
- Originator: scjones@thor
-
- In article <4cpv1n$apm@der.twinsun.com>, eggert@twinsun.com (Paul Eggert) writes:
- > Since this is comp.std.c, I'll mention that the (x + y < x) != (y < 0) method
- > and Daniel Wood's example both port to any C implementation
- > claiming conformance to LIA-1 (ISO/IEC 10967-1:1994(E),
- > `Information technology -- Language independent arithmetic -- Part 1:
- > Integer floating point arithmetic' <ftp://crl.dec.com/pub/misc/lia-1-dis.ps.Z>)
- > if INT_MODULO is true (which is the only plausible value for INT_MODULO
- > for real-world C compilers).
-
- The current thinking about binding LIA-1 to C allows signed and unsiged
- integers to have different behavior. Whilst unsigned integers *have*
- to be MODULO for standard conformance, there is no good reason for
- signed integers to be the same (other than that many existing machine
- architectures make it very inconvenient to have them be different).
- Some (many?) people think that raising an exception of some kind for
- signed integer overflow is very desirable, rather than allowing the
- answer to quietly wrap around.
- ----
- Larry Jones, SDRC, 2000 Eastman Dr., Milford, OH 45150-2789 513-576-2070
- larry.jones@sdrc.com
- Some people just don't have inquisitive minds. -- Calvin
-
