I hope this patch suits you better :-)

I've updated the documentation typo (thanks for pointing that out). I've also changed 'c' to 'x', since I think that if there is a convention we should stick to it.  I don't think that it matters if the glibc docs say 'exclusive', as long it its clear in the python docs what it does, which I think it is. Having said that, I don't really have a strong opinion either way, so I'll happily change it back to 'c' if its preferred.