exp, expf, expl - base-e exponential function

```
#include <math.h>
double exp(double x);
float expf(float x);
long double expl(long double x);
```

Link with `-lm`

.

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

```
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
```

These functions return the value of e (the base of natural logarithms) raised to the power of `x`

.

On success, these functions return the exponential value of `x`

.

If `x`

is a NaN, a NaN is returned.

If `x`

is positive infinity, positive infinity is returned.

If `x`

is negative infinity, +0 is returned.

If the result underflows, a range error occurs, and zero is returned.

If the result overflows, a range error occurs, and the functions return +**HUGE_VAL**, +**HUGE_VALF**, or +**HUGE_VALL**, respectively.

See math_error(7) for information on how to determine whether an error has occurred when calling these functions.

The following errors can occur:

- Range error, overflow
`errno`

is set to**ERANGE**. An overflow floating-point exception (**FE_OVERFLOW**) is raised.- Range error, underflow
`errno`

is set to**ERANGE**. An underflow floating-point exception (**FE_UNDERFLOW**) is raised.

For an explanation of the terms used in this section, see attributes(7).

Interface | Attribute | Value |

exp(), expf(), expl() | Thread safety | MT-Safe |

C99, POSIX.1-2001, POSIX.1-2008.

The variant returning `double`

also conforms to SVr4, 4.3BSD, C89.

cbrt(3), cexp(3), exp10(3), exp2(3), expm1(3), sqrt(3)

This page is part of release 4.15 of the Linux `man-pages`

project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.