@c ----------------------------------------------------------------------
@node frexp, math
@subheading Syntax

@example
#include <math.h>

double frexp(double x, int *pexp);
@end example

@subheading Description

This function separates the given value @var{x} into a mantissa m in the
range @code{[0.5,1)} and an exponent e, such that @math{m*2^e = @var{x}}.
It returns the value of the mantissa and stores the integer exponent in
@var{*pexp}.

@subheading Return Value

The mantissa.  If the value of @var{x} is @code{NaN} or @code{Inf}, the
return value is @code{NaN}, zero is stored in @code{*pexp}, and
@code{errno} is set to @code{EDOM}.  If @var{x} is zero, @var{*pexp} and
the return value are also both zero.

@subheading Portability

@portability ansi, posix