Returning Boolean

[Steve Hay]

Just a quick question:

Is there a "preferred way" to return a Boolean value from an XSUB?

I could have an SV* function returning &PL_sv_yes/&PL_sv_no (or 
&PL_sv_undef?), or a bool function returning TRUE/FALSE, or even just an 
int function returning 1/0.

Is there any advantage in any of these?

Steve