Linux Programmer’s Manual
cosh, coshf, coshl − hyperbolic cosine function
double cosh(double x);
float coshf(float x);
long double coshl(long double x);
Link with −lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
coshf(), coshl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||
_ISOC99_SOURCE; or cc -std=c99
The cosh() function returns the hyperbolic cosine of x, which is defined mathematically as:
cosh(x) = (exp(x) + exp(−x)) / 2
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 returned.
If the result overflows, a range error occurs, and the functions return +HUGE_VAL, +HUGE_VALF, or
See math_error(7) for information on how to determine whether an error has occurred when calling these
The following errors can occur:
Range error: result overflow
errno is set to ERANGE. An overflow floating-point exception (FE_OVERFLOW) is raised.
C99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD.
In glibc version 2.3.4 and earlier, an overflow floating-point (FE_OVERFLOW) exception is not raised
when an overflow occurs.
acosh(3), asinh(3), atanh(3), ccos(3), sinh(3), tanh(3)
This page is part of release 3.24 of the Linux man-pages project. A description of the project, and informa-
tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.