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 later

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.

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

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