.TH FREXP 2
.SH NAME
frexp, ldexp, modf \- split into mantissa and exponent
.SH SYNOPSIS
.B #include <u.h>
.br
.B #include <libc.h>
.PP
.B
double frexp(double value, int *eptr)
.PP
.B
double ldexp(double value, int exp)
.PP
.B
double modf(double value, double *iptr)
.SH DESCRIPTION
.I Frexp
returns the mantissa of
.I value
and stores the exponent indirectly through
.IR eptr ,
so that
.I value
=
.if t .IR frexp ( value )×2\u\s-2 (*eptr) \s0\d
.if n .IR frexp ( value )*2** (*eptr).
.PP
.I Ldexp
returns the quantity
.if t .IR value ×2\u\s-2 exp \s0\d.
.if n .IR value *2** exp.
.PP
.I Modf
returns the positive fractional part of
.I value
and stores the integer part indirectly
through
.IR iptr .
.SH SOURCE
.B /sys/src/libc/port/frexp.c
.SH SEE ALSO
.IR intro (2)
.SH DIAGNOSTICS
.I Ldexp
returns 0 for underflow and the appropriately signed infinity
for overflow.