exp man page

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)):

expf(), expl():

|| /* 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.

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.


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).

exp(), expf(), expl()Thread safetyMT-Safe

Conforming to

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

The variant returning double also conforms to SVr4, 4.3BSD, C89.

See Also

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

Referenced By

erf(3), erfc(3), exp10(3), exp2(3), expm1(3), log1p(3).

Explore man page connections for exp(3).

expf(3) and expl(3) are aliases of exp(3).