expanding variadic into format

[Codifies]

I have a routine that was happily printing ASCII strings and 
values using opengl, however I want to improve it so it can be 
used in the same manner as some other languages printf function...

void printValue(Font fnt,float x, float y, string frmt, ...)
{
     /* matrix math and other stuff removed for readability */
     string message = format(frmt, _arguments);


no surprise this naive attempt causes a runtime error as its 
trying to format a range using the first format specifier in frmt

am I going to have to chop frmt into descrete chunks that have 
just one % symbol in them and then build up the formatted message 
string like that?

is there some way to somehow transfer my input variadic into 
formats variadic ?