The CLONG() function converts its argument to a signed 24-bit value.

DECLARE FUNCTION CLONG AS LONG (number AS BYTE) SHARED STATIC INLINE
DECLARE FUNCTION CLONG AS LONG (number AS INT) OVERLOAD SHARED STATIC INLINE
DECLARE FUNCTION CLONG AS LONG (number AS WORD) OVERLOAD SHARED STATIC INLINE
DECLARE FUNCTION CLONG AS LONG (number AS FLOAT) OVERLOAD SHARED STATIC INLINE

If the argument is a FLOAT, it will be rounded and then converted to LONG.