exp, expf, expl

Calculates the exponential.

Syntax

double exp(
   double x
);
float exp(
   float x
);  // C++ only
long double exp(
   long double x
);  // C++ only
float expf(
   float x
);
long double expl(
   long double x
);
#define exp(z) // Requires C11 or higher

Parameters

x
The floating-point value to exponentiate the natural logarithm base e by.

Return value

The exp functions return the exponential value of the floating-point parameter, x, if successful. That is, the result is e^x, where e is the base of the natural logarithm. On overflow, the function returns INF (infinity) and on underflow, exp returns 0.

Input	SEH exception	_matherr exception
± Quiet NaN, indeterminate	None	_DOMAIN
± Infinity	INVALID	_DOMAIN
x ≥ 7.097827e+002	INEXACT+OVERFLOW	OVERFLOW
x ≤ -7.083964e+002	INEXACT+UNDERFLOW	UNDERFLOW

The exp function has an implementation that uses Streaming SIMD Extensions 2 (SSE2). See _set_SSE2_enable for information and restrictions on using the SSE2 implementation.

Remarks

C++ allows overloading, so you can call overloads of exp that take a float or long double argument. In a C program, unless you're using the <tgmath.h> macro to call this function, exp always takes and returns a double.

If you use the exp macro from <tgmath.h>, 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

Function	Required C header	Required C++ header
exp, expf, expl	<math.h>	<cmath> or <math.h>
exp macro	<tgmath.h>

For more compatibility information, see Compatibility.

Example

// crt_exp.c

#include <math.h>
#include <stdio.h>

int main( void )
{
   double x = 2.302585093, y;

   y = exp( x );
   printf( "exp( %f ) = %f\n", x, y );
}

exp( 2.302585 ) = 10.000000

See also

Math and floating-point support
log, logf, log10, log10f
_CIexp