EXP(3) Library Functions Manual EXP(3)

exp — exponential function

#include <math.h>

double exp(double x);

The exp() function computes the exponent of x, defined as e x .

An application wishing to check for error situations should set errno to 0 before calling exp(). If errno is non-zero on return, or the return value is NaN, an error has occurred.

Upon successful completion, exp() returns the exponential value of x .

If the correct value would cause overflow, exp() returns HUGE_VAL and sets errno to [ERANGE].

If the correct value would cause underflow, exp() returns 0 and may set errno to [ERANGE].

If is NaN, NaN is returned and errno may be set to [EDOM].

The exp() function will fail if:

The result overflows.

The exp() function may fail if:

The value of x is NaN.
The result underflows.

No other errors will occur.

None.

None.

None.

isnan(3) , log(3) , <math.h> .

Derived from Issue 1 of the SVID.

February 1997 posix.fail