\" $NetBSD: ldexp.3,v 1.5 2016/03/17 18:29:59 nros Exp $
\"
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\" @(#)ldexp.3 8.2 (Berkeley) 4/19/94
\"
Dd March 17, 2016
Dt LDEXP 3
Os
Sh NAME
Nm ldexp ,
Nm ldexpf ,
Nm ldexpl
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"
Ft long double
Fn ldexpl "long double x" "int exp"
Sh DESCRIPTION
The
Fn ldexp
family of functions compute
Bd -ragged -offset indent
Va x
*
2^\fIexp\fR
Ed
Pp
for a real floating-point number
Fa x .
Sh RETURN VALUES
The functions return the value of
Fa x
times 2 raised to the power
Fa exp .
Otherwise the following may occur:
Bl -enum -offset indent
It
If
Fa x
is \*(Na, a \*(Na is returned.
It
If
Fa exp
is zero or
Fa x
is either \*(Pm 0 or \*(Pm\[if],
Fa x
is returned.
It
If the call would cause an overflow, a range error occurs and either
Dv \*(Pm\*HHUGE_VAL ,
Dv \*(Pm\*HHUGE_VALF ,
or
Dv \*(Pm\*HHUGE_VALL
is returned, depending on the sign of
Fa x
and the type of the return value.
It
If an underflow would be caused by the correct value,
and the value is not representable, either 0.0 or
an implementation-defined value is returned.
El
Sh SEE ALSO
Xr frexp 3 ,
Xr math 3 ,
Xr modf 3
Sh STANDARDS
The described functions conform to
St -isoC-99 .
