`exp2`, `exp2f`, `exp2l`

2022-12-02

Computes 2 raised to the specified value.

Syntax

double exp2(
   double x
);

float exp2(
   float x
);  // C++ only

long double exp2(
   long double x
); // C++ only

float exp2f(
   float x
);

long double exp2l(
   long double x
);
#define exp2(X) // Requires C11 or later

Parameters

x
The value of the exponent.

Return value

If successful, returns the base-2 exponent of x, that is, 2^x. Otherwise, it returns one of the following values:

Issue	Return
`x` = ±0	1
`x` = -INFINITY	+0
`x` = +INFINITY	+INFINITY
`x` = NaN	NaN
Overflow range error	+HUGE_VAL, +HUGE_VALF, or +HUGE_VALL
Underflow range error	Correct result, after rounding

Errors are reported as specified in _matherr.

Remarks

Because C++ allows overloading, you can call overloads of exp2 that take and return float and long double types. In a C program, unless you're using the <tgmath.h> macro to call this function, exp2 always takes and returns a double, unless you use the macro in <tgmath.h>.

If you use the <tgmath.h> exp2() macro, the type of the argument determines which version of the function is selected. See Type-generic math for details.

By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.

Requirements

Routine	C header	C++ header
`exp2`, `expf2`, `expl2`	<math.h>	<cmath>
`exp2` macro	<tgmath.h>

For more compatibility information, see Compatibility.

Feedback

Var den här sidan till hjälp?

Dela via

exp2, exp2f, exp2l