AT&T UNIX™PC Unix System V Users Manual - tenox

FREXP ( 3C ) FREXP ( 3C )
NAME
frexp, ldexp, modf - manipulate parts of floating-point numbers
SYNOPSIS
double frexp (value, eptr)
double value;
int *eptr;
double ldexp (value, exp)
double value;
int exp;
double modf (value, iptr)
double value, •iptr;
DESCRIPTION
Every non-zero number can be written uniquely as x * 2 n , where
the "mantissa" (fraction) x is in the range 0.5 :::; I x I < 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 .
Ldexp returns the quantity value * 2 e:rp .
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 and errno is set
to ERANGE.
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