EXP(3M) | Mathematical Library Functions | EXP(3M) |

exp, expf, expl - exponential function

c99 [flag... ]file...-lm[library... ] #include <math.h>doubleexp(doublex);

floatexpf(floatx);

long doubleexpl(long doublex);

These functions compute the base-*e* exponential of
*x*.

Upon successful completion, these functions return the exponential
value of *x*.

If the correct value would cause overflow, a range error occurs
and **exp()**, **expf()**, and **expl()** return **HUGE_VAL**,
**HUGE_VALF**, and **HUGE_VALL**, respectively.

If *x* is NaN, a NaN is returned.

If *x* is ±0, 1 is returned.

If *x* is +Inf, *x* is returned.

For exceptional cases, matherr(3M) tabulates the values to
be returned by **exp()** as specified by SVID3 and XPG3. See
standards(7).

These functions will fail if:

**Range Error**

The result overflows.

If the integer expression (**math_errhandling** &
**MATH_ERREXCEPT**) is non-zero, the overflow floating-point exception is
raised.

The **exp()** function sets **errno** to **ERANGE** if
the result overflows.

An application wanting to check for exceptions should call
**feclearexcept**(**FE_ALL_EXCEPT**) before calling these functions.
On return, if **fetestexcept**(**FE_INVALID** | **FE_DIVBYZERO** |
**FE_OVERFLOW** | **FE_UNDERFLOW**) is non-zero, an exception has been
raised. An application should either examine the return value or check the
floating point exception flags to detect exceptions.

An application can also set **errno** to 0 before calling
**exp()**. On return, if **errno** is non-zero, an error has occurred.
The **expf()** and **expl()** functions do not set **errno**.

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE | ATTRIBUTE VALUE |

Interface Stability | Standard |

MT-Level | MT-Safe |

math.h(3HEAD), feclearexcept(3M), fetestexcept(3M), isnan(3M), log(3M), matherr(3M), mp(3MP), attributes(7), standards(7)

July 12, 2006 | SunOS 5.11 |