scalbln

, scalblnf

, scalblnl

, scalbn

, scalbnf

, scalbnl

- compute exponent using FLT_RADIX

Synopsis

c99 [ flag... ] file... -lm [ library... ]
#include <math.h>

double scalbln(double x, long n);

float scalblnf(float x, long n);

long double scalblnl(long double x, long n);

double scalbn(double x, int n);

float scalbnf(float x, int n);

long double scalbnl(long double x, int n);

Description

These functions compute x * FLT_RADIXⁿ efficiently, not normally by computing FLT_RADIXⁿ explicitly.

Return Values

Upon successful completion, these functions return x * FLT_RADIXⁿ>.

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

If x is NaN, a NaN is returned.

If x is ±0 or ±Inf, x is returned.

If x is 0, x is returned.

Errors

These functions will fail if:

Range Error

The result overflows.

If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point exception is raised.

Usage

An application wanting to check for exceptions should call feclearexcept(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:

See Also

feclearexcept(3M), fetestexcept(3M), math.h(3HEAD), scalb(3M), attributes(5), standards(5)