frexp(3C) — sys5



FREXP(3C)       DOMAIN/IX Reference Manual (SYS5)       FREXP(3C)



NAME
     frexp, ldexp, modf - manipulate parts of floating-point
     numbers

USAGE
     double frexp (value, eptr)
     double value;
     int *eptr;

     double ldexp (value, exp)
     double value;
     int exp;

     double modf (value, iptr)
     double value, *iptr;

DESCRIPTION
                                                          n
     Every non-zero number can be written uniquely as x* 2 ,
     where the ``mantissa'' (fraction) x is in the range 0.5 <
     |x| < 1.0, and the ``exponent'' n is an integer.  Frexp
     returns the mantissa of a double value, and stores the
     exponent indirectly in the location pointed to by eptr.  If
     value is zero, both results returned by frexp are zero.

                                        exp
     Ldexp returns the quantity value* 2   .

     Modf returns the signed fractional part of value and stores
     the integral part indirectly in the location pointed to by
     iptr.

DIAGNOSTICS
     If ldexp would cause overflow, +HUGE is returned (according
     to the sign of value), and errno is set to ERANGE.

     If ldexp would cause underflow, zero is returned and errno
     is set to ERANGE.



















Printed 5/10/85                                           FREXP-1
Museum
