[xml] calling xmlCleanupParser from a library considered harmful

hi all,

authors of libraries that use libxml2 internally for whatever reason
should take note that calling xmlCleanupParser frees various bits of
global state and as a result makes libxml2 effectively unusable for any
other code in the process that also happens to use libxml2, and hence
makes your library effectively un-usable (until the offending call is
patched out).


This function name is somewhat misleading. It does not clean up 
parser state, it cleans up memory allocated by the library itself.
It is a cleanup function for the XML library. It tries to reclaim
all related global memory allocated for the library processing. One
should call xmlCleanupParser() only when the process has finished
using the library [...] WARNING: if your application is
multithreaded or has plugin support calling this may crash the
application if another thread or a plugin is still using libxml2.

please do not _ever_ call xmlCleanupParser from a library.

LibreOffice has been hit for the second time[1] now by some library
calling xmlCleanupParser; a colleague much smarter than me wasted many
hours tracking that down as the root cause of an obscure crash involving
CUPS and thread local storage... which finally motivated me to add this
hack (should work on ELF platforms) so the next time the problem is
easier to detect:



[1] pedantic note: technically at the first time it was OpenOffice.org

[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]