COS(3)                    (2017-09-15)                     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
          attributes(7).     allbox;    lbw21    lb    lb   l   l   l.
          Interface Attribute Value   T{   cos(),    cosf(),    cosl()
          T}   Thread safety  MT-Safe

     CONFORMING TO

     Page 1                       Plan 9             (printed 5/20/22)

     COS(3)                    (2017-09-15)                     COS(3)

          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/.

     Page 2                       Plan 9             (printed 5/20/22)