On 4/10/2014 16:53, Bart De Schuymer wrote:
On Thu, Apr 10, 2014 at 2:30 PM, Nikolay Sivov <bungleh...@gmail.com
<mailto:bungleh...@gmail.com>> wrote:
On 4/10/2014 16:20, Bart De Schuymer wrote:
Hello,
We tried using libxml2 configured with the --with-fexceptions
option and have identified a memory leak when our C++
startElement callback throws an exception.
The cause of the leak is as follows:
xmlParseStartTag frees all attribute values after calling the
startElement callback, but since an exception is thrown in the
callback, this cleanup code isn't executed.
xmlFreeParserCtxt only frees ctxt->atts: it doesn't try to free
any leftover attribute values.
We tried to patch libxml2 to fix this issue but ran into errors
when running make valgrind ("Memory tag error occurs"). So we
decided to catch the exceptions in our callback instead which
effectively prevents the memory leak from occurring.
Yes, you should handle that on your side. libxml2 is a C library,
so you can't handle cpp features in it, you could try of course to
maintain your own version of libxml2 extended with exception
handler wrappers for all callbacks you need, but it's a strange
thing to do.
I see. If that's the official statement then it is a bad idea to offer
the --with-fexceptions flag at configuration time. Especially since
there is no mention of the accompanying memory leaks.
No, I'm not speaking officially and I'm not involved in libxml2
development, this is just my opinion. I mean it seems natural to me that
cpp specific features won't work for C lib, as another commenter
mentioned you might consider cpp wrappers with corresponding exception
support. Can't comment on this gcc flag though.
Best regards,
Bart
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