On 2010-04-07 04:06, Bruno Haible wrote:
I was implicitly hoping that
- gcc would collect all weak-declared symbols in some table, and
generate code so that the reference to these symbols makes an indirection
through this table,
- the Cygwin runtime would call dlsym or GetProcAddr
Dave Korn wrote:
>> I've got some code, written for ELF platforms, that detects whether the
>> pthread library (often a separate library from libc) is linked, by doing
>>
>> #pragma weak pthread_cancel
>> bool pthread_in_use = (pthread_cancel != NULL);
>
> And you really need to determine this
On 07/04/2010 10:06, Bruno Haible wrote:
> Thanks for these explanations. So, "#pragma weak" is very different on PE
> systems than on ELF systems.
Well, to be pedantically precise, "#pragma weak" is basically the same: it
shuts the linker up from complaining about a symbol if no definition is
On 4/7/2010 5:06 AM, Bruno Haible wrote:
> I've got some code, written for ELF platforms, that detects whether the
> pthread
> library (often a separate library from libc) is linked, by doing
>
> #pragma weak pthread_cancel
> bool pthread_in_use = (pthread_cancel != NULL);
>
> This code brea
Hi Dave,
> on ELF platforms, you can leave undefined references in an executable, to
> be filled in by ld.so at runtime according to what the loader finds present
> once it's loaded libc.
> ...
> On windows ... There's no run-time process of
> scanning all available symbols from all loaded libr
ygwin, 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.
>
>
Hi Dave,
Dave Korn wrote:
> >> 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
>
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