usr/src/lib/libc/gen/frexp.3

.\"     @(#)frexp.3     6.3 (Berkeley) %G%
.\"
.TH FREXP 3 ""
.AT 3
.SH NAME
frexp, ldexp, modf \- split into mantissa and exponent
.SH SYNOPSIS
.nf
.B double frexp(value, eptr)
.B double value;
.B int *eptr;
.PP
.B double ldexp(value, exp)
.B double value;
.PP
.B double modf(value, iptr)
.B double value, *iptr;
.SH DESCRIPTION
Every nonzero number can be written uniquely as
.if t \fIx\fP\|\(**\|2\u\fIn\fP\d,
.if n \fIx\fP * 2^\fIn\fP,
where the ``mantissa'' (fraction) \fIx\fP is in the range 0.5 <= |x| < 1.0,
and the ``exponent'' \fIn\fP is an integer.  \fIFrexp\fP returns the
mantissa of a double \fIvalue\fP, and stores the exponent indirectly in
the location pointed to by \fIeptr\fP.  If \fIvalue\fP is 0, both results
returned by \fIfrexp\fP are 0.
.PP
\fILdexp\fP returns the quantity
.if t \fIvalue\|\(**\|2\u\fIexp\fP\d.
.if n \fIvalue\fP * 2^\fIexp\fP.
.PP
\fIModf\fP returns the signed fractional part of \fIvalue\fP
and stores the integer part indirectly in the location pointed
to by \fIiptr\fP.
.SH DIAGNOSTICS
If \fIldexp\fP would cause overflow, \fBHUGE\fP is returned
and \fIerrno\fP is set to \fBERANGE\fP.