## Linux and UNIX Man Pages

Test Your Knowledge in Computers #55
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# acos(3m) [sunos man page]

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

NAME
acos, acosf, acosl - arc cosine functions

SYNOPSIS
cc [ 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, ] 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			   |
+-----------------------------+-----------------------------+

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

SunOS 5.10							    1 Sep 2001								  acos(3M)```

## Check Out this Related Man Page

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

NAME
acos, acosf, acosl - arc cosine functions

SYNOPSIS
cc [ 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, ] 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			   |
+-----------------------------+-----------------------------+