exp, expf, expl - base-e exponential function
Math library (libm
, -lm
)
#include <math.h>
double exp(double x);
float expf(float x);
long double expl(long double x);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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:
errno
is set to ERANGE. An overflow
floating-point exception (FE_OVERFLOW) is raised.
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 |
Thread safety | MT-Safe |
C11, POSIX.1-2008.
C99, POSIX.1-2001.
The variant returning double
also conforms to SVr4, 4.3BSD,
C89.