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Re: [Proposed binutils PATCH] Re: Diagnosing an intricate C++problem


>>>>> "Jason" == Jason Merrill <jason@redhat.com> writes:

    Jason>  http://gcc.gnu.org/ml/gcc/2000-07/msg00769.htm

CenterLine had possibly now-patented technology on doing ODR checking
by using hashing.  Care was taken not to diagnose "harmless" ODR
violations (which happen far more often than you might think).  For
example, it turned out that some of the Sun headers did something like
`#define foo bar' where `foo' was in the user namespace.  So, in real
programs, half of the files had `foo' replaced with `bar' everywhere;
this is an ODR violation, but not one that is harmful, or easy for
users to fix.  So, the ODR checker had a "sloppy" mode where it
allowed things like this, and also like `extern int x' in one file and
`long x' in another, if the `int' and `long' had the same number of
bits.

The possible patent-holders are friends of mine, and it is possible
that they would license the technology for use in GCC at no cost.  It
is also possible that they would not.  It is also possible that a
non-infringing alternative could be found.

--
Mark Mitchell                   mark@codesourcery.com
CodeSourcery, LLC               http://www.codesourcery.com

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