FUNCTION bit2int, bitin, checkneg = checkneg
;
  compile_opt idl2, strictarrsubs
;

  res = 0L
  n = n_elements(bitin)-1
  IF keyword_set(checkneg) THEN BEGIN
    IF bitin[0] EQ 1 THEN BEGIN
      bitin[0] = 0
      neg = -1
    ENDIF ELSE neg = 1
  ENDIF ELSE neg = 1
  FOR i = 0, n  DO res = res+2L^i*bitin[n-i]

  RETURN, neg*res
END