EXP2(3M) Mathematical Library Functions EXP2(3M)

exp2, exp2f, exp2l - exponential base 2 functions

c99 [ flag... ] file... -lm [ library... ]
#include <math.h>
double exp2(double x);

float exp2f(float x);

long double exp2l(long double x);

These functions compute the base-2 exponential of x.

Upon successful completion, these functions return 2^x.

If the correct value would cause overflow, a range error occurs and exp2(), exp2f(), and exp2l() return the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL, respectively.

If x is NaN, a NaN is returned.

If x is ±0, 1 is returned.

If x is −Inf, +0 is returned.

If x is +Inf, x is returned.

These functions will fail if:

Range Error

The result overflows.

If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, the overflow floating-point exception will be raised.

An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.

See attributes(7) for descriptions of the following attributes:

Interface Stability Standard
MT-Level MT-Safe

math.h(3HEAD), exp(3M), feclearexcept(3M), fetestexcept(3M), isnan(3M), log(3M), attributes(7), standards(7)

July 12, 2006 SunOS 5.11