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EXP 3M "Jul 12, 2006" "SunOS 5.11" "Mathematical Library Functions"
NAME
exp, expf, expl - exponential function
SYNOPSIS

```c99 [ flag... ] file... -lm [ library... ]
#include <math.h>

double exp(double x);
```

```float expf(float x);
```

```long double expl(long double x);
```
DESCRIPTION

These functions compute the base-e exponential of x.

RETURN VALUES

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(5).

ERRORS

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.

USAGE

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.

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

 ATTRIBUTE TYPE ATTRIBUTE VALUE Interface Stability Standard MT-Level MT-Safe