The BOOST_PP_FRAME_START macro expands to the lower bound of an absolute file-iteration depth.
	
	Usage
		
			BOOST_PP_FRAME_START(i)
		
	Arguments
		
			- i
- 
				The absolute depth of the frame whose lower bound is to be retreived. 
				Valid values range from 1 to BOOST_PP_ITERATION_DEPTH().
			
Remarks
		
			This macro is only valid when a file-iteration is in progress.
		
	Requirements