exp2
, exp2f
, exp2l
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 higher
Parameters
x
The value of the exponent.
Return value
If successful, returns the base-2 exponent of x
, that is, 2x. 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.
See also
Alphabetical function reference
exp
, expf
, expl
log2
, log2f
, log2l
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