exp(3) Library Functions Manual exp(3)
NAME
exp, expf, expl - base-e exponential function
LIBRARY
Math library (libm, -lm)
SYNOPSIS
#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)):
expf(), expl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
DESCRIPTION
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.
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.
ATTRIBUTES
For an explanation of the terms used in this section, see at-
tributes(7).
┌────────────────────────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├────────────────────────────────────────────┼───────────────┼─────────┤
│exp(), expf(), expl() │ Thread safety │ MT-Safe │
└────────────────────────────────────────────┴───────────────┴─────────┘
STANDARDS
C99, POSIX.1-2001, POSIX.1-2008.
The variant returning double also conforms to SVr4, 4.3BSD.
SEE ALSO
cbrt(3), cexp(3), exp10(3), exp2(3), expm1(3), sqrt(3)
Linux man-pages 6.03 2023-02-05 exp(3)
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