minix/lib/nbsd_libm/man/ldexp.3

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.\" $NetBSD: ldexp.3,v 1.1 2006/07/03 16:03:56 drochner Exp $
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.\" @(#)ldexp.3 8.2 (Berkeley) 4/19/94
.\"
.Dd March 21, 2006
.Dt LDEXP 3
.Os
.Sh NAME
.Nm ldexp
.Nd multiply floating-point number by integral power of 2
.Sh LIBRARY
.Lb libm
.Sh SYNOPSIS
.In math.h
.Ft double
.Fn ldexp "double x" "int exp"
.Ft float
.Fn ldexpf "float x" "int exp"
.Sh DESCRIPTION
The
.Fn ldexp
function multiplies a floating-point number by an integral
power of 2.
.Sh RETURN VALUES
The
.Fn ldexp
function returns the value of
.Fa x
times 2 raised to the power
.Fa exp .
.Pp
If the input
.Va x
is a NaN, infinity, or 0.0, it is returned unchanged.
.Pp
If the result would cause an overflow,
the global variable
.Va errno
is set to
.Er ERANGE
and infinity is returned, with the same sign as
.Fa x .
.Pp
If the result would cause underflow to 0.0,
the global variable
.Va errno
is set to
.Er ERANGE
and the value 0.0 is returned.
.Sh SEE ALSO
.Xr frexp 3 ,
.Xr math 3 ,
.Xr modf 3
.Sh STANDARDS
The
.Fn ldexp
function conforms to
.St -ansiC .