cos, cosf, cosl − cosine function
Math library (libm, −lm)
#include <math.h>
double
cos(double x);
float cosf(float x);
long double cosl(long double x);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
cosf(),
cosl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
These functions return the cosine of x, where x is given in radians.
On success, these functions return the cosine of x.
If x is a NaN, a NaN is returned.
If x is positive infinity or negative infinity, a domain error occurs, and a NaN is returned.
See math_error(7) for information on how to determine whether an error has occurred when calling these functions.
The following
errors can occur:
Domain error: x is an infinity
errno is set to EDOM (but see BUGS). An invalid floating-point exception (FE_INVALID) is raised.
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For an explanation of the terms used in this section, see attributes(7). |
C11, POSIX.1-2008.
C89, POSIX.1-2001.
The variant returning double also conforms to SVr4, 4.3BSD.
Before glibc 2.10, the glibc implementation did not set errno to EDOM when a domain error occurred.
acos(3), asin(3), atan(3), atan2(3), ccos(3), sin(3), sincos(3), tan(3)