scalbn, scalbnf—scale by power of two #include <math.h>
double scalbn(double x, int y);
float scalbnf(float x, int y);
Description
scalbn and scalbnf scale x by n, returning x times
2 to the power n. The result is computed by manipulating the
exponent, rather than by actually performing an exponentiation or
multiplication.
Returns
x times 2 to the power n.
Portability
Neither scalbn nor scalbnf is required by ANSI C or by the System V
Interface Definition (Issue 2).