[xml] xmlGenericErrorFunc error handling

["Jason Aeschilman" <jason fatpipeinc com>]

Other people on this list pointed out that if you're creating your own error
handler, you have to deal with your error handler being called multiple
times for a single error.  So here is my question:

How can I safely gather the entire error message and output it to a log file
in one line?

What I have done to work around this so far is to store all the pieces of
the error message in a static buffer (static char *) until I receive the
piece (string) that ends in a newline character, then I copy the buffer to
my logging function (also prepending "libxml:" to it).  Therefore, I'm
making the assumption that I will eventually get a string that ends in a
newline character.  I'm not sure if that's a safe assumption.

Jason

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Registering the callback:
xmlSetGenericErrorFunc(NULL, (xmlGenericErrorFunc)libxml_log);
Defining the callback function:
void libxml_log(void *ctx, const char *msg, ...) { }