scalb(3M) Mathematical Library Functions scalb(3M)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 float‐
ing-point exception is raised.
USAGE
An application wanting to check for exceptions should call feclearex‐
cept(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 TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼───────────────────────────────┤
│Interface Stability │Committed │
├─────────────────────────────┼───────────────────────────────┤
│MT-Level │MT-Safe │
├─────────────────────────────┼───────────────────────────────┤
│Standard │For scalb(), see standards(5). │
└─────────────────────────────┴───────────────────────────────┘
SEE ALSOfeclearexcept(3M), fetestexcept(3M), ilogb(3M), ldexp(3M), logb(3M),
math.h(3HEAD), matherr(3M), scalbln(3M), attributes(5), standards(5)SunOS 5.11 12 Jul 2006 scalb(3M)
