**#include <math.h>
**

**
double scalbln(double** *x***, long** *n***);
float scalblnf(float**

long double scalblnl(long double

double scalbn(double

float scalbnf(float

long double scalbnl(long double

These functions shall compute *x* * FLT_RADIX***n* efficiently,
not normally by
computing FLT_RADIX***n* explicitly.

An application wishing to check for error situations should set *errno*
to zero and call
*feclearexcept*(FE_ALL_EXCEPT) before calling these functions.
On return, if *errno* is non-zero or
*fetestexcept*(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW)
is non-zero, an error has occurred.

Upon successful completion, these functions shall return *x* * FLT_RADIX***n*.

If the result would cause overflow, a range error shall occur and
these functions shall return ±HUGE_VAL,
±HUGE_VALF, and ±HUGE_VALL (according to the sign of *x*)
as appropriate for the return type of the
function.

If the correct value would cause underflow, and is not representable, a range error may occur, and either 0.0 (if supported), or an implementation-defined value shall be returned.

If
*x* is NaN, a NaN shall be returned.

If *x* is ±0 or ±Inf, *x* shall be returned.

If *n* is 0, *x* shall be returned.

If the correct value would cause underflow, and is representable, a range error may occur and the correct value shall be returned.

These functions shall fail if:

- Range Error
- The result overflows.

If the integer expression (math_errhandling & MATH_ERRNO) is non-zero,
then *errno* shall be set to [ERANGE]. If the
integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero,
then the overflow floating-point exception shall be
raised.

These functions may fail if:

- Range Error
- The result underflows.

If the integer expression (math_errhandling & MATH_ERRNO) is non-zero,
then *errno* shall be set to [ERANGE]. If the
integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero,
then the underflow floating-point exception shall be
raised.

*The following sections are informative.*

On error, the expressions (math_errhandling & MATH_ERRNO) and (math_errhandling & MATH_ERREXCEPT) are independent of each other, but at least one of them must be non-zero.

These functions are named so as to avoid conflicting with the historical
definition of the *scalb*() function from the Single UNIX Specification.
The difference is that the *scalb*() function has a second argument
of **double** instead of **int**. The *scalb*() function is
not part of the ISO C standard. The three functions whose second
type
is **long** are provided because the factor required to scale from
the smallest positive floating-point value to the largest
finite one, on many implementations, is too large to represent in
the minimum-width **int** format.

*feclearexcept*() , *fetestexcept*() , *scalb*() , the
Base Definitions volume of IEEE Std 1003.1-2001, Section 4.18, Treatment
of Error Conditions for Mathematical Functions, *<math.h>*

- NAME
- SYNOPSIS
- DESCRIPTION
- RETURN VALUE
- ERRORS
- EXAMPLES
- APPLICATION USAGE
- RATIONALE
- FUTURE DIRECTIONS
- SEE ALSO
- COPYRIGHT

Time: 21:54:21 GMT, April 16, 2011