exp, expf, expl

Header: <math.h>

1-3) Computes e (Euler’s number, 2.7182818…) raised to the given power arg.

# Declarations

float expf( float arg );

(since C99)

double exp( double arg );

long double expl( long double arg );

(since C99)

#define exp( arg )

(since C99)

# Parameters

# Return value

If no errors occur, the base-e exponential of arg (earg) is returned.

# Notes

For IEEE-compatible type double, overflow is guaranteed if 709.8 < arg, and underflow is guaranteed if arg < -708.4.

# Example

#include <errno.h>
#include <fenv.h>
#include <float.h>
#include <math.h>
#include <stdio.h>
// #pragma STDC FENV_ACCESS ON
 
int main(void)
{
    printf("exp(1) = %f\n", exp(1));
    printf("FV of $100, continuously compounded at 3%% for 1 year = %f\n",
            100*exp(0.03));
    // special values
    printf("exp(-0) = %f\n", exp(-0.0));
    printf("exp(-Inf) = %f\n", exp(-INFINITY));
    //error handling
    errno = 0; feclearexcept(FE_ALL_EXCEPT);
    printf("exp(710) = %f\n", exp(710));
    if (errno == ERANGE)
        perror("    errno == ERANGE");
    if (fetestexcept(FE_OVERFLOW))
        puts("    FE_OVERFLOW raised");
}

# See also