Standards
| Standards / Extensions | C or C++ | Dependencies |
|---|---|---|
XPG4.2 |
both |
Format
#define _XOPEN_SOURCE_EXTENDED 1
#include <math.h>
double scalb(double x, double n);General description
The scalb()
function computes 
.
If n is not an integer,
it is silently truncated.
Note: This function works in both IEEE
Binary Floating-Point and hexadecimal floating-point formats. The radix is
16 for hexadecimal floating-point and 2 for IEEE Binary Floating-Point.
See IEEE binary floating-point for more information
about IEEE Binary Floating-Point.
Returned value
If it succeeds, scalb() returns the function of its arguments as described above.
scalb() will
fail under the following conditions:
- If the result would underflow, scalb() will return 0 and set errno to ERANGE.
- If the result would overflow, scalb() will return ±HUGE_VAL according to the sign of x and set errno to ERANGE.
Special behavior for IEEE: If successful, scalb() returns the value of the x parameter times 2 to the power of the y parameter.
If the result would overflow, scalb() returns ±HUGE_VAL according to the sign of x and sets errno to ERANGE. No other errors can occur.