Re: [xml] register i/o callback functionality

["Rob Richards" <rrichards ctindustries net>]

From: Mike Hommey

> Well, let's take a simple case :
> One module wants to format output with indentation.
> Another wants to format output without.
> So, the first sets xmlIndentTreeOutput to 1, and then calls
> xmlDumpFormatMemory.
> The second sets xmlIndentTreeOutput to 0, and then calls
> xmlDumpFormatMemory.
> When the two of them are not called "simulteanously", this is not a
> problem. But now imagine this multithreaded scenario :
> second module sets xmlIndentTreeOutput to 0
> first module sets xmlIndentTreeOuput to 1
> first module outputs
> second module outputs
> Well, it seems to me that the second module has made an indented output
> while not expected to...

You should look at globals.h/c (particularly the xmlInitializeGlobalState
function for a list of handled vars/functions). This will show you how your
scenario would be handled (each thread would be able to handle its own state
without interfering with other threads).

Rob