Header File 

float.h 

Category 

Math Routines 

Prototype 

double _scalb(double d, long exp); 

long double _scalbl(long double ld, long exp); 

Description 

Scales the argument d by a power of 2. 

_scalbl is the long double version; it takes a long double argument and returns a long double result. 

Return Value 

Returns an exponential value if successful. On overflow (depending on the sign of the argument), the function returns +/– HUGE_VAL; the ERRNO variable is set to ERANGE. 

Portability