[xslt] best way to get result as a string?

[Marc Respass <marcrespass mac com>]

Hi,

I am getting a compiler warning that I would like to get rid of. I'm  
writing a Mac OS X (Cocoa) app and using the XSL library. The warning is

pointer targets in passing argument 1 of 'stringWithUTF8String:'  
differ in signedness

I call xsltApplyStylesheet() then xsltSaveResultToString() to get the  
result into a string which is a unsigned char xmlChar *. I then  
create an NSString using -stringWithUTF8String: which takes a const  
char * and get the signedness warning.

My reading of Kernighan and Ritchie makes me feel like there is a  
chance that this could break but I don't know any way around it. Am I  
correct in thinking that const char * is signed since it does not  
specify? I haven't found that in the book and I would not expect a  
warning if the default is unsigned. Maybe there is a different  
function I could call to get the transformation result as a const  
char *? I didn't see anything in the libxml docs.

Thanks
Marc