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.\" Copyright 2004 Andries Brouwer <aeb@cwi.nl>.
.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
.\" <mtk.manpages@gmail.com>
.\"
.\" %%%LICENSE_START(VERBATIM)
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date. The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein. The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\" %%%LICENSE_END
.\"
.TH SCALBLN 3 2020-11-01 "" "Linux Programmer's Manual"
.SH NAME
scalbn, scalbnf, scalbnl, scalbln, scalblnf, scalblnl \-
multiply floating-point number by integral power of radix
.SH SYNOPSIS
.B #include <math.h>
.PP
.BI "double scalbln(double " x ", long " exp );
.br
.BI "float scalblnf(float " x ", long " exp );
.br
.BI "long double scalblnl(long double " x ", long " exp );
.PP
.BI "double scalbn(double " x ", int " exp );
.br
.BI "float scalbnf(float " x ", int " exp );
.br
.BI "long double scalbnl(long double " x ", int " exp );
.PP
Link with \fI\-lm\fP.
.PP
.RS -4
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.RE
.PP
.ad l
.BR scalbln (),
.BR scalblnf (),
.BR scalblnl ():
.RS
_ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
.RE
.br
.BR scalbn (),
.BR scalbnf (),
.BR scalbnl ():
.RS
_ISOC99_SOURCE || _POSIX_C_SOURCE\ >=\ 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
.RE
.ad b
.SH DESCRIPTION
These functions multiply their first argument
.I x
by
.B FLT_RADIX
(probably 2)
to the power of
.IR exp ,
that is:
.PP
.nf
x * FLT_RADIX ** exp
.fi
.PP
The definition of
.B FLT_RADIX
can be obtained by including
.IR <float.h> .
.\" not in /usr/include but in a gcc lib
.SH RETURN VALUE
On success, these functions return
.IR x
*
.B FLT_RADIX
**
.IR exp .
.PP
If
.I x
is a NaN, a NaN is returned.
.PP
If
.I x
is positive infinity (negative infinity),
positive infinity (negative infinity) is returned.
.PP
If
.I x
is +0 (\-0), +0 (\-0) is returned.
.PP
If the result overflows,
a range error occurs,
and the functions return
.BR HUGE_VAL ,
.BR HUGE_VALF ,
or
.BR HUGE_VALL ,
respectively, with a sign the same as
.IR x .
.PP
If the result underflows,
a range error occurs,
and the functions return zero, with a sign the same as
.IR x .
.SH ERRORS
See
.BR math_error (7)
for information on how to determine whether an error has occurred
when calling these functions.
.PP
The following errors can occur:
.TP
Range error, overflow
.\" .I errno
.\" is set to
.\" .BR ERANGE .
An overflow floating-point exception
.RB ( FE_OVERFLOW )
is raised.
.TP
Range error, underflow
.I errno
is set to
.BR ERANGE .
An underflow floating-point exception
.RB ( FE_UNDERFLOW )
is raised.
.SH VERSIONS
These functions first appeared in glibc in version 2.1.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lbw33 lb lb
l l l.
Interface Attribute Value
T{
.BR scalbn (),
.BR scalbnf (),
.BR scalbnl (),
.br
.BR scalbln (),
.BR scalblnf (),
.BR scalblnl ()
T} Thread safety MT-Safe
.TE
.SH CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
.SH NOTES
These functions differ from the obsolete functions described in
.BR scalb (3)
in the type of their second argument.
The functions described on this page have a second argument
of an integral type, while those in
.BR scalb (3)
have a second argument of type
.IR double .
.PP
If
.B FLT_RADIX
equals 2 (which is usual), then
.BR scalbn ()
is equivalent to
.BR ldexp (3).
.SH BUGS
Before glibc 2.20,
.\" http://sources.redhat.com/bugzilla/show_bug.cgi?id=6803
these functions did not set
.I errno
for range errors.
.SH SEE ALSO
.BR ldexp (3),
.BR scalb (3)
.SH COLOPHON
This page is part of release 5.09 of the Linux
.I man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
\%https://www.kernel.org/doc/man\-pages/.
|
