HP 3000 Manuals

HP C/iX Library Reference Manual

acos 

Returns the arc cosine in radians of the input value.

Syntax 

     #include <math.h>
     double acos (double x);

Parameters 

x             A real number.

Return Values 

n             The arc cosine of x.

0             The magnitude of the argument of acos is greater than one
              or less than negative one.  In addition, errno is set to
              EDOM.

Description 

The acos function returns the arc cosine of x, in the range of zero to
pi.  A message indicating a DOMAIN error is printed on the standard error
output if x is greater than one or less than negative one.

Error-handling can be changed by a user-written matherr function.

See Also 

matherr(), ANSI C 4.5.2.1, POSIX.1 8.1

MPE/iX 5.0 Documentation