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);
expf(),
expl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 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.
cbrt(3),
cexp(3),
exp10(3),
exp2(3),
expm1(3),
sqrt(3)