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Name

exp, expf, expl - base-e exponential function

Synopsis


#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) ):

expf(), expl():

_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
or cc -std=c99

Description

The exp() function returns the value of e (the base of natural logarithms) raised to the power of x.

Return Value

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.

Errors

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.

Conforming to

C99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD, C89.

See Also

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

Colophon

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