Re: Weak c++ symbols refresher needed
On Tue, Oct 07, 2014 at 04:23:54PM +0800, Chow Loong Jin wrote:
> On Tue, Oct 07, 2014 at 09:37:48AM +0200, Mathieu Malaterre wrote:
> > I am starring at bug #758572. Basically OP reports that `cmake` is
> > underlinked, which is a serious issue as per policy. However when
> > reading the details it appears that this is a c++ weak symbol (AFAIK
> > no weak default definition is available). This weak symbol is
> > generated by default by gcc when using part of the STL (See
> > #758572#13).
No, he shows that using a different libcurl makes ld.so barf. He
provides no evidence that the weak symbol is the reason for this.
> > Could someone please remind me in which case weak symbols (no weak
> > default definition) can trigger an undefined behavior at runtime ?
> I think UB is only triggered if something attempts to use the symbol. Is cmake pulling in
> another library that uses libpthread but doesn't link it in?
No, this is perfectly valid. Weak symbols are initialized to zero if no
definition is found.
Bastian
--
Those who hate and fight must stop themselves -- otherwise it is not stopped.
-- Spock, "Day of the Dove", stardate unknown
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