pro keytest2,keyw=keyw

IF KEYWORD_SET(keyw) THEN BEGIN
    HELP,keyw
    PRINT,'The value of "keyw" is ',keyw
    keyw=1B
    ENDIF

RETURN
END

PRO keytest1,keyw=keyw

IF KEYWORD_SET(keyw) THEN PRINT,'In keytest1, the value of "keyw" is ',keyw,' before keytest2.'
keytest2,keyw=keyw
IF KEYWORD_SET(keyw) THEN PRINT,'In keytest1, the value of "keyw" is ',keyw,' after keytest2.'
return
end