Mathematical Library Functions                           asin(3M)



NAME
     asin, asinf, asinl - arc sine function

SYNOPSIS
     c99 [ flag... ] file... -lm [ library... ]
     #include 

     double asin(double x);


     float asinf(float x);


     long double asinl(long double x);


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

RETURN VALUES
     Upon successful completion, these functions return  the  arc
     sine of x in the range [-pi/2, pi/2] radians.


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


     If x is NaN, NaN is returned.


     If x is ]0, x is returned.


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


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

ERORS
     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  (matherrhandling
                     &  MATHEREXCEPT)  is non-zero, the invalid
                     floating-point exception is raised.




SunOS 5.11          Last change: 12 Jul 2006                    1






Mathematical Library Functions                           asin(3M)



                     The asin() 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(FEALEXCEPT) before calling these functions.
     On  return,  if  fetestexcept(FEINVALID    FEDIVBYZERO  
     FEOVERFLOW    FEUNDERFLOW)  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
     asin().  On  return,  if  errno  is  non-zero,  an error has
     occurred. The asinf()  and  asinl()  functions  do  not  set
     errno.

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Standard                    
    
     MT-Level                     MT-Safe                     
    


SEE ALSO
     isnan(3M),       feclearexcept(3M),        fetestexcept(3M),
     math.h(3HEAD),  matherr(3M),  sin(3M),  attributes(5), stan-
     dards(5)
















SunOS 5.11          Last change: 12 Jul 2006                    2