Computes the base 2 exponential.
#include <math.h> double exp2 (x) double x; float exp2f (x) float x; long double exp2l (x) long double x;
The exp2, exp2f, and exp2l subroutines compute the base 2 exponential of the x parameter.
An application wishing to check for error situations should set the errno global variable to zero and call feclearexcept (FE_ALL_EXCEPT) before calling these subroutines. On return, if errno is nonzero or fetestexcept (FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is nonzero, an error has occurred.
x | Specifies the base 2 exponential to be computed. |
Upon successful completion, the exp2, exp2f, or exp2l subroutine returns 2x .
If the correct value causes overflow, a range error occurs and the exp2, exp2f, and exp2l subroutines return the value of the macro (HUGE_VAL, HUGE_VALF, and HUGE_VALL, respectively).
If the correct value causes underflow and is not representable, a range error occurs, and 0.0 is returned.
If x is NaN, NaN is returned.
If x is ±0, 1 is returned.
If x is -Inf, 0 is returned.
If x is +Inf, x is returned.
If the correct value would cause underflow, and is representable, a range error may occur and the correct value is returned.
math.h in AIX 5L Version 5.2 Files Reference.