acos(3) [suse man page]

ACOS(3) 						     Linux Programmer's Manual							   ACOS(3)

NAME

       acos, acosf, acosl - arc cosine function

SYNOPSIS

       #include <math.h>

       double acos(double x);
       float acosf(float x);
       long double acosl(long double x);

       Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       acosf(), acosl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or cc -std=c99

DESCRIPTION

       The acos() function calculates the arc cosine of x; that is the value whose cosine is x.

RETURN VALUE

       On success, these functions return the arc cosine of x in radians; the return value is in the range [0, pi].

       If x is a NaN, a NaN is returned.

       If x is +1, +0 is returned.

       If x is positive infinity or negative infinity, a domain error occurs, and a NaN is returned.

       If x is outside the range [-1, 1], 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 outside the range [-1, 1]
	      errno is set to EDOM.  An invalid floating-point exception (FE_INVALID) is raised.

CONFORMING TO

       C99, POSIX.1-2001.  The variant returning double also conforms to SVr4, 4.3BSD, C89.

SEE ALSO

       asin(3), atan(3), atan2(3), cacos(3), cos(3), sin(3), tan(3)

COLOPHON

       This  page is part of release 3.25 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

								    2008-08-05								   ACOS(3)

acos(3M)						  Mathematical Library Functions						  acos(3M)

NAME

       acos, acosf, acosl - arc cosine functions

SYNOPSIS

       c99 [ flag... ] file... -lm [ library... ]
       #include <math.h>

       double acos(double x);

       float acosf(float x);

       long double acosl(long double x);

DESCRIPTION

       These functions compute the principal value of the arc cosine of x. The value of x should be in the range [-1,1].

RETURN VALUES

       Upon successful completion, these functions return the arc cosine of x in the range [0, pi] radians.

       For finite values of  x not in the range [-1,1], a domain error occurs and NaN is returned.

       If x is NaN, NaN is returned.

       If x is +1, +0 is returned.

       If x is +-Inf, a domain error occurs and NaN is returned.

       For exceptional cases, matherr(3M) tabulates the values to be returned by acos() as specified by SVID3 and XPG3.

ERRORS

       These functions will fail if:

       Domain Error    The x argument is finite and not in the range [-1,1], or is +-Inf.

		       If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, the invalid floating-point exception is raised.

		       The acos() function sets errno to EDOM if x is not +-Inf or NaN and is not in the range [-1,1].

USAGE

       An  application	wanting  to  check  for  exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if
       fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception  has  been  raised.  An  application  should
       either examine the return value or check the floating point exception flags to detect exceptions.

       An  application	can  also  set	errno  to 0 before calling acos(). On return, if errno is non-zero, an error has occurred. The acosf() and
       acosl() functions do not set errno.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       cos(3M), feclearexcept(3M), fetestexcept(3M), isnan(3M), math.h(3HEAD), matherr(3M), attributes(5), standards(5)

SunOS 5.11							    12 Jul 2006 							  acos(3M)