The BOOST_PP_SUB macro expands to the difference between its arguments.
	
	Usage
		
			BOOST_PP_SUB(x, y)
		
	Arguments
		
			- x
- 
				The minuend of the operation. 
				Valid values range from 0 to BOOST_PP_LIMIT_MAG.
			
- y
- 
				The subtrahend of the operation. 
				Valid values range from 0 to BOOST_PP_LIMIT_MAG.
			
Remarks
		
			If the difference between x and y is less than 0, the result is saturated to 0.
		
		
			Previously, this macro could not be used inside BOOST_PP_WHILE. 
			There is no longer any such restriction. 
			It is more efficient, however, to use BOOST_PP_SUB_D in such a situation.
		
	See Also
		
	Requirements
		
	Sample Code