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Date: Tue, 06 Apr 2010 03:15:45 +0100
From: Dave Korn <dave DOT korn DOT cygwin AT googlemail DOT com>
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To: cygwin AT cygwin DOT com
Subject: Re: test results on Cygwin
References: <201004051747 DOT 40474 DOT bruno AT clisp DOT org> <201004052348 DOT 22022 DOT bruno AT clisp DOT org> <4BBA5C54 DOT 9040702 AT redhat DOT com>
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On 05/04/2010 22:55, Eric Blake wrote:
> [moving to the cygwin list from bug-gnulib]
> 
> On 04/05/2010 03:48 PM, Bruno Haible wrote:
>>> Failures on Cygwin 1.7.2
>>> ------------------------
>>>
>>> Starting test_cond .../bin/sh: line 5:  4200 Aborted
>>> FAIL: test-cond.exe
>>>
>>> Starting test_lock .../bin/sh: line 5:  2296 Aborted
>>> FAIL: test-lock.exe
>>>
>>> Starting test_tls .../bin/sh: line 5:  2656 Aborted
>>> FAIL: test-tls.exe
>> These were all due to the fact that gcc 4.3.x on Cygwin 1.7.2
>> accepts "#pragma weak foo", but the symbol foo then evaluates
>> to the NULL address, even if foo is defined in libc.
> 
> Dave, are weak symbols something that should work on cygwin with new
> enough binutils/gcc?  Or is this an indicator of a gcc bug, for silently
> accepting #pragma weak foo that it can't support?

  Weak symbols work on Cygwin, but the semantics of undefined weak symbols
aren't identical to ELF platforms: a weak reference won't pull in an archive
member that wouldn't otherwise be linked; the implications in relation to
import libraries should be fairly obvious.  Also, I haven't actually verified
that "#pragma weak" is hooked up to DTRT in the same way as using a weak
attribute on a declaration (but also have no particular reason to suspect it
wouldn't work).

    cheers,
      DaveK

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