scalb, scalbf, scalbl - multiply floating-point number by integral power of radix (OBSOLETE)
#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)):
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>
.
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
.
See math_error(7) for information on how to determine whether an error has occurred when calling these functions.
The following errors can occur:
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 NaNAn invalid floating-point exception (FE_INVALID) is raised.
An overflow floating-point exception (FE_OVERFLOW) is raised.
An underflow floating-point exception (FE_UNDERFLOW) is raised.
These functions do not set errno
.
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value |
scalb(), scalbf(), scalbl() | Thread safety | MT-Safe |
scalb() is specified in POSIX.1-2001, but marked obsolescent. POSIX.1-2008 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
This page is part of release 4.15 of the Linux 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/.