3. Library calls (functions within program libraries)
SCALB
Section: Linux Programmer's Manual (3)Updated: 20170915
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NAME
scalb, scalbf, scalbl  multiply floatingpoint number by integral power of radix (OBSOLETE)SYNOPSIS
#include <math.h>
double scalb(double x, double exp);
float scalbf(float x, float exp);
long double scalbl(long double x, long double exp);
Link with lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
scalb():

_XOPEN_SOURCE >= 500
 /* Since glibc 2.19: */ _DEFAULT_SOURCE
 /* Glibc versions <= 2.19: */ _BSD_SOURCE  _SVID_SOURCE
scalbf(), scalbl():

_XOPEN_SOURCE >= 600
 /* Since glibc 2.19: */ _DEFAULT_SOURCE
 /* Glibc versions <= 2.19: */ _BSD_SOURCE  _SVID_SOURCE
DESCRIPTION
These functions multiply their first argument x by FLT_RADIX (probably 2) to the power of exp, that is:
x * FLT_RADIX ** exp
The definition of FLT_RADIX can be obtained by including <float.h>.
RETURN VALUE
On success, these functions return x * FLT_RADIX ** exp.If x or exp is a NaN, a NaN is returned.
If x is positive infinity (negative infinity), and exp is not negative infinity, positive infinity (negative infinity) is returned.
If x is +0 (0), and exp is not positive infinity, +0 (0) is returned.
If x is zero, and exp is positive infinity, a domain error occurs, and a NaN is returned.
If x is an infinity, and exp is negative infinity, a domain error occurs, and a NaN is returned.
If the result overflows, a range error occurs, and the functions return HUGE_VAL, HUGE_VALF, or HUGE_VALL, respectively, with a sign the same as x.
If the result underflows, a range error occurs, and the functions return zero, with a sign the same as x.
ERRORS
See math_error(7) for information on how to determine whether an error has occurred when calling these functions.The following errors can occur:
 Domain error: x is 0, and exp is positive infinity, or x is positive infinity and exp is negative infinity and the other argument is not a NaN
 An invalid floatingpoint exception (FE_INVALID) is raised.
 Range error, overflow
 An overflow floatingpoint exception (FE_OVERFLOW) is raised.
 Range error, underflow
 An underflow floatingpoint exception (FE_UNDERFLOW) is raised.
These functions do not set errno.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).Interface  Attribute  Value 
scalb(), scalbf(), scalbl()  Thread safety  MTSafe 
CONFORMING TO
scalb() is specified in POSIX.12001, but marked obsolescent. POSIX.12008 removes the specification of scalb(), recommending the use of scalbln(3), scalblnf(3), or scalblnl(3) instead. The scalb() function is from 4.3BSD.scalbf() and scalbl() are unstandardized; scalbf() is nevertheless present on several other systems
SEE ALSO
ldexp(3), scalbln(3)COLOPHON
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