C in a Nutshell

Name

scalbln, scalbn

Synopsis

Multiplies a floating-point number by a power of the floating-point radix

#include <math.h>
doublescalbn( double x, int n );
float scalbnf( float x, int n );
long double scalbnl( long double x, int n );

double scalbln( double x, long int n );
float scalblnf( float x, long int n );
long double scalblnl( long double x, long int n );

The scalbn() and scalbln() functions multiply a floating-point number x by an integer power of FLT_RADIX, providing a more efficient calculation than the arithmetic operators. The symbolic constant FLT_RADIX, defined in float.h, indicates the base of the floating-point environment’s exponent representation; this is usually 2, for binary exponent representation. In this case, the return value of the scalbn() and scalbln() functions is x × 2ⁿ.

Example

See the example for feholdexcept() in this chapter.

See Also

frexp(), ldexp()