cosh(3) Library Functions Manual cosh(3)
NAME
cosh, coshf, coshl - hyperbolic cosine function
LIBRARY
Math library (libm, -lm)
SYNOPSIS
#include <math.h>
double cosh(double x);
float coshf(float x);
long double coshl(long double x);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
coshf(), coshl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
DESCRIPTION
These functions return the hyperbolic cosine of x, which is defined
mathematically as:
cosh(x) = (exp(x) + exp(-x)) / 2
RETURN VALUE
On success, these functions return the hyperbolic cosine of x.
If x is a NaN, a NaN is returned.
If x is +0 or -0, 1 is returned.
If x is positive infinity or negative infinity, positive infinity is re-
turned.
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: result overflow
errno is set to ERANGE. An overflow floating-point exception
(FE_OVERFLOW) is raised.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
┌────────────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├────────────────────────────────────────────┼───────────────┼─────────┤
│ cosh(), coshf(), coshl() │ Thread safety │ MT-Safe │
└────────────────────────────────────────────┴───────────────┴─────────┘
STANDARDS
C11, POSIX.1-2008.
HISTORY
C99, POSIX.1-2001.
The variant returning double also conforms to SVr4, 4.3BSD.
BUGS
In glibc 2.3.4 and earlier, an overflow floating-point (FE_OVERFLOW) ex-
ception is not raised when an overflow occurs.
SEE ALSO
acosh(3), asinh(3), atanh(3), ccos(3), sinh(3), tanh(3)
Linux man-pages 6.9.1 2024-05-02 cosh(3)
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