COS(3) Linux Programmer's Manual COS(3)
NAME
 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 at-
 tributes(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
 This page is part of release 5.10 of the Linux man-pages project. A
 description of the project, information about reporting bugs, and the
 latest version of this page, can be found at
 https://www.kernel.org/doc/man-pages/.
 2017年09月15日 COS(3)