Re: [xml] wrong startElement called

["Robert G. Ristroph" <rristroph airlinksystems com>]

Quoting Eric Haszlakiewicz <erh+libxml nimenees com>:

> On Tue, Nov 09, 2004 at 04:17:13PM -0600, Robert G. Ristroph wrote:
> >     On the computer where the program crashes, the stack trace shows it
enters
> > the functions startElement which is in legacy.c at line 1397.  On the
> computer
> > that works, it calls a startElement that is in my own code, a wrapper
> around
> > libxml2.
> >
> >     What might be causing the code to call one startElement() on one
> machine and
> > a different one on the other ?  I have been struggling with this for some
> time,
> > and I have already checked the versions and file sizes of all the .so
> libraries
> > the program uses.
>
>       Perhaps a bug in the dynamic linker?  Or maybe a difference in the order
> that libraries are loaded.  Depending on whether your code or the libxml
> code
> is loaded first, the value stored in the PLT for the actual pointer to the
> startElement function can be different.  I'm not quite sure what the
> behavior
> is supposed to be when you have two identically named global symbols (as
> you seem to have)

I no longer have the problem.  Since I fixed it by installing a new version of
PHP from source, without changing version of xmllib or the way I used xmllib,
it seems likely that the cause is something like this.

> >     There is a "static xmlSAXHandler sax" which is defined in my code
> which
> > holds a pointer to my startElement.
>
>       How is your startElement function defined?  Is it static also?
> The easiest way I can think of to fix your problem is just rename your
> function.  Doesn't your linker spit out a warning when you link you
> code?
>
> The other solution, which should only be used if the libxml startElement
> function should be allowed to be overridden, is to make it a weak symbol
> alias in the library.

My startElement is not defined as a static, although I can see from comments in
my code that at one time it was.  This is something I'll have to look at
carefully and make sure we are doing it the right way, and I'll probably rename
it.

--Rob



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