integer isnan(r)
c
c	title:
c	*****
c
c	  isnan -- test for missing real*4 value
c
c	purpose:
c	*******
c
c	  to test for a real number flagged as missing
c
c	parameters:
c	**********
c
c	  r     -> real value to test
c	  isnan <- 0 iff number, 1 iff missing
c
	  real r
c
c	code:
c	****
c
	if(r.eq.9.9e37) then
		isnan = 1
	else
		isnan = 0
	endif
c
c	/* return */
c
	return
c
c	end isnan
c
	end