minix/lib/libm/man/scalbn.3
Lionel Sambuc 84d9c625bf Synchronize on NetBSD-CVS (2013/12/1 12:00:00 UTC)
- Fix for possible unset uid/gid in toproto
 - Fix for default mtree style
 - Update libelf
 - Importing libexecinfo
 - Resynchronize GCC, mpc, gmp, mpfr
 - build.sh: Replace params with show-params.
     This has been done as the make target has been renamed in the same
     way, while a new target named params has been added. This new
     target generates a file containing all the parameters, instead of
     printing it on the console.
 - Update test48 with new etc/services (Fix by Ben Gras <ben@minix3.org)
     get getservbyport() out of the inner loop

Change-Id: Ie6ad5226fa2621ff9f0dee8782ea48f9443d2091
2014-07-28 17:05:06 +02:00

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.\" $NetBSD: scalbn.3,v 1.2 2011/09/18 05:33:14 jruoho Exp $
.\"
.\" Copyright (c) 2011 Jukka Ruohonen <jruohonen@iki.fi>
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.Dd September 18, 2011
.Dt SCALBN 3
.Os
.Sh NAME
.Nm scalbn ,
.Nm scalbnf ,
.Nm scalbnl
.Nd exponent using FLT_RADIX
.Sh LIBRARY
.Lb libm
.Sh SYNOPSIS
.In math.h
.Ft double
.Fn scalbn "double x" "int n"
.Ft float
.Fn scalbnf "float x" "int n"
.Ft long double
.Fn scalbnl "long double x" "int n"
.Sh DESCRIPTION
The
.Fn scalbn ,
.Fn scalbnf ,
and
.Fn scalbnl
functions compute
.Fa x
*
.Fa r^n ,
where
.Fa r
is the radix of the machine's floating point arithmetic, defined by the
.Dv FLT_RADIX
constant in
.In float.h .
The rationale is efficiency;
.Fa r^n
is not computed explicitly.
.Sh RETURN VALUES
As described above, upon successful completion, the described functions return
the exponent computed using
.Dv FLT_RADIX .
Otherwise the following may occur:
.Pp
.Bl -enum -offset indent
.It
When the result would cause an overflow, a range error occurs and
.Dv \*(Pm\*HHUGE_VAL ,
.Dv \*(Pm\*HHUGE_VALF ,
or
.Dv \*(Pm\*HHUGE_VALL
is returned according to the sign of
.Fa x
and the return type of the corresponding function.
.It
When the correct value would cause an underflow
and it is not representable, a range error occurs and
either 0.0 or an implementation-defined value is returned.
When an underflow occurs but the correct value is representable,
a range error occurs but the correct value is returned.
.It
If
.Fa x
is \*(Pm0 or \*(Pm\Inf,
.Fa x
is returned.
Likewise, if
.Fa n
is zero,
.Fa x
is returned.
If
.Fa x
is \*(Na, \*(Na is returned.
.El
.Sh SEE ALSO
.Xr exp 3 ,
.Xr frexp 3 ,
.Xr ldexp 3 ,
.Xr math 3
.Sh STANDARDS
The described functions conform to
.St -isoC-99 .