Section (3) scalb
scalb, scalbf, scalbl — multiply floating-point number by integral power of radix (OBSOLETE)
||long double x,|
|long double exp
These functions multiply their first argument
FLT_RADIX (probably 2) to the power of
exp, that is:
x * FLT_RADIX ** exp
The definition of
can be obtained by including
On success, these functions return
exp is a NaN, a NaN is
x is positive
infinity (negative infinity), and
exp is not negative infinity,
positive infinity (negative infinity) is returned.
x is +0
is not positive infinity, +0 (−0) is returned.
x is zero, and
exp is positive
infinity, a domain error occurs, and a NaN is returned.
x is an
negative infinity, a domain error occurs, and a NaN is
If the result overflows, a range error occurs, and the
HUGE_VALL, respectively, with a sign the
If the result underflows, a range error occurs, and the
functions return zero, with a sign the same as
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:
xis 0, and
expis positive infinity, or
xis positive infinity and
expis negative infinity and the other argument is not a NaN
An invalid floating-point exception (
FE_INVALID) is raised.
- Range error, overflow
An overflow floating-point exception (
FE_OVERFLOW) is raised.
- Range error, underflow
An underflow floating-point exception (
FE_UNDERFLOW) is raised.
These functions do not set
For an explanation of the terms used in this section, see attributes(7).
scalb() is specified in
POSIX.1-2001, but marked obsolescent. POSIX.1-2008 removes
the specification of
recommending the use of scalbln(3), scalblnf(3), or scalblnl(3) instead. The
scalb() function is from
scalbl() are unstandardized;
scalbf() is nevertheless present on several
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