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Re: [v3] Fix / clean-up config vs crosses (5/n): avoid a TRY_RUN
Paolo Carlini wrote:
>> B. Test at run-time, the first time you want to use the special file.
>>
> In this specific case, I think this is unfortunately a no-no, because
> the layout of a class changes depending on that test and it's too late
> to change it. For C++0x I'll make sure to design things differently...
Yes, breaking ABI compatibility is of course a major issue, so I
wouldn't suggest doing that. Obviously, run-time checks impose some
overhead, but for future situations similar to this, it might be the
best thing. You have to open the file anyhow; if the open fails, then
set a global variable and fall back to Plan B. I would suspect that the
cost would be pretty low. Anyhow...
As for GCC_CHECK_UNWIND_GETIPINFO, that looks like something that could
be a compile-time test (on all targets, whether or not native). As
discussed previously, it really *should* be a link-time test, but unless
people are willing to rethink the one-tree build stuff, we're not
allowed link-time tests.
And, as for AM_ICONV, unfortunately, I'm totally iconv-illiterate. :-(
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Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713