RE: [xml] xmlDocDump crashing on windows

I think it is in principle impossible/inadvisable/bad to use both versions
of the Windows runtime libraries anywhere in your libraries and application.
That's why there are often 4 versions of every Windows library. 2
(debug/release) * 2 (the 2 runtimes) = 4.

Murray Cumming
murrayc usa net

-----Original Message-----
From: xml-admin gnome org [mailto:xml-admin gnome org] On 
Behalf Of Igor Zlatkovic
Sent: Donnerstag, 27. November 2003 15:56
To: Eric Zurcher csiro au
Cc: xml gnome org
Subject: Re: [xml] xmlDocDump crashing on windows

<Igor changed the subject line to fit the thread>

Eric Zurcher csiro au wrote:

I guess I'm not surprised that you get a crash in this 
context. If I 
understand things correctly, when the application and the 
libxml2 DLL 
are using different run-time libraries, they're each going to have 
their own "stdout", with their own file-locking mechanism in the 
multi-threaded case. The DLL is going to have trouble accessing a 
"stdout" which is under the control of the main application's 

The situation is a bit like trying to use malloc in the main 
application, then passing the resulting pointer to a DLL 
and expecting 
it to be able to free it. It can work if the runtime is in 
common, but 
will fail otherwise.

Perhaps it might be useful if libxml2 exported its version of the 
standard IO units (e.g, xmlStdIn, xmlStdOut, xmlStdErr), so 
that the 
application could use them in API functions that make use 
of a FILE* 
as an argument. I suppose there could even be an xmlFOpen and 

Does that make sense to anyone else, or am I way off base here?

How would you declare these? With stdin and friends I guess 
it would be okay 
to have functions which return the desired file descriptor, 
but what about 

In a production version, memory functions are macros which resolve to 
malloc/free. These will always be tied to the runtime of any 
module at 
compilation time. The only solution for this is to remove 
macros and use 
functions which have their implementation in libxml and do 
nothing else but 
delegating the call to malloc/free.

For one, this would break the binary compatibility. For two, 
this would 
introduce an additional function call per allocation. How 
much impact on the 
performance would that give? Note that this will propagate to 
that uses libxml, ie libxslt, xmlsec, GNOME...

In every case, people will eat our hearts if we break the 
ABI, unless we go 
to libxml3 and do it there. Also, if the performance 
degradation is more 
than three nanoseconds, noone will want to have it.

It certainly would make sense to isolate all the differences 
between the 
underlying runtimes and handle them in one place, in a 
generic way, so that 
everyone can use what she pleases and never get a problem. I 
just don't see 
a way to do it. Everything I can think of breaks the ABI.


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