Calculates the value of 2 raised to the power d.
long double exp2l(long double d);
d Floating-point number for which exponential function is to be computed
Normal: Exponential function value of 2
Abnormal: Range error: Returns 0, or returns +HUGE_VAL, +HUGE_VALF, or +HUGE_VALL depending on the function
A range error occurs if the absolute value of d is too large.