powi

Syntax

#include <math.h> double powi(double x, int iy);

Description

This function computes x^iy, where iy is an integer number. It does so by an optimized sequence of squarings and multiplications. For integer values of exponent, it is always faster to call powi than to call pow with the same arguments, even if iy has a very large value. For small values of iy, powi is much faster than pow.

Return Value

x raised to the iy power. If x and iy are both zero, the return value is 1. If x is equal to zero, and iy is negative, the return value is Inf. This function never sets errno.

Portability

ANSI/ISO C	No
POSIX	No