cos, cosf, cosl — cosine function
Synopsis
#include <math.h> double cos(double x); float cosf(float x); long double cosl(long double x);
Link with -lm.
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 versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
Description
These functions return the cosine of x, where x is given in radians.
Return Value
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.
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:
- Domain error: x is an infinity
errno is set to EDOM (but see Bugs). An invalid floating-point exception (FE_INVALID) is raised.
Attributes
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
|---|---|---|
| cos(), cosf(), cosl() | Thread safety | MT-Safe |
Conforming to
C99, POSIX.1-2001, POSIX.1-2008.
The variant returning double also conforms to SVr4, 4.3BSD.
Bugs
Before version 2.10, the glibc implementation did not set errno to EDOM when a domain error occurred.
See Also
acos(3), asin(3), atan(3), atan2(3), ccos(3), sin(3), sincos(3), tan(3)
Colophon
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Referenced By
acos(3), asin(3), atan(3), atan2(3), dlopen(3), sin(3), sincos(3), tan(3).
The man pages cosf(3) and cosl(3) are aliases of cos(3).