[xml] xmlNewTextReaderFilename , detect cause of failure ?

[Jeroen Cranendonk <j cranendonk emaxx nl>]

Hi, quicky question :)

I use xmlNewTextReaderFilename to create a new file based 
xmlTextReader. This function returns 0 on error.

When I receive 0, how do I detect the cause of this error ?
(most specificly, how do I find out if we ran out of memory, or if there was
some file-io error, for example :)

I can see in the code xmllib keeps this info, but I can't really make heads
or tails of the many error handling stuff in there :)

I'm looking for a way to do this that is libxml 2.5 compatible :)

Many thanks, don't forget to cc a reply to me ^-^ (hit reply all ;)
        Jeroen C.