xref: /illumos-gate/usr/src/man/man3m/scalb.3m (revision 8808ac5dae118369991f158b6ab736cb2691ecde)
te
Copyright (c) 2001, the Institute of Electrical and Electronics Engineers, Inc. and The Open Group. All Rights Reserved.
Copyright (c) 1992, X/Open Company Limited. All Rights Reserved.
Portions Copyright (c) 2006, Sun Microsystems, Inc. All Rights Reserved.
Sun Microsystems, Inc. gratefully acknowledges The Open Group for permission to reproduce portions of its copyrighted documentation. Original documentation from The Open Group can be obtained online at
http://www.opengroup.org/bookstore/.
The Institute of Electrical and Electronics Engineers and The Open Group, have given us permission to reprint portions of their documentation. In the following statement, the phrase "this text" refers to portions of the system documentation. Portions of this text are reprinted and reproduced in electronic form in the Sun OS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html.
This notice shall appear on any product containing this material.
The contents of this file are subject to the terms of the Common Development and Distribution License (the "License"). You may not use this file except in compliance with the License.
You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing. See the License for the specific language governing permissions and limitations under the License.
When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE. If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
scalb 3M "12 Jul 2006" "SunOS 5.11" "Mathematical Library Functions"
NAME
scalb, scalbf, scalbl - load exponent of a radix-independent floating-point number
SYNOPSIS

c99 [ flag... ] file... -lm [ library... ]
#include <math.h>

double scalb(double x, double n);

float scalbf(float x, float n);

long double scalbl(long double x, long double n);
DESCRIPTION

These functions compute x * r^n, where r is the radix of the machine's floating point arithmetic. When r is 2, scalb() is equivalent to ldexp(3M). The value of r is FLT_RADIX which is defined in <float.h>.

RETURN VALUES

Upon successful completion, the scalb() function returns x * r^n.

If x or n is NaN, a NaN is returned.

If n is 0, x is returned.

If x is \(+-Inf and n is not -Inf, x is returned.

If x is \(+-0 and n is not +Inf, x is returned.

If x is \(+-0 and n is +Inf, a domain error occurs and a NaN is returned.

If x is \(+-Inf and n is -Inf, a domain error occurs and a NaN is returned.

If the result would cause an overflow, a range error occurs and \(+-HUGE_VAL (according to the sign of x) is returned.

For exceptional cases, matherr(3M) tabulates the values to be returned by scalb() as specified by SVID3 and XPG3. See standards(5).

ERRORS

These functions will fail if:

Domain Error

If x is 0 and n is +Inf, or x is Inf and n is -Inf. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception is raised.

Range Error

The result would overflow. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point exception is raised.

USAGE

An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPEATTRIBUTE VALUE
Interface StabilitySee below.
MT-LevelMT-Safe

The scalb() function is Standard. The scalbf() and scalbl() functions are Stable.

SEE ALSO

feclearexcept(3M), fetestexcept(3M), ilogb(3M), ldexp(3M), logb(3M), math.h(3HEAD), matherr(3M), scalbln(3M), attributes(5), standards(5)