Mathematical Library Functions                         tgamma(3M)



NAME
     tgamma, tgammaf, tgammal - compute gamma function

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

     double tgamma(double x);


     float tgammaf(float x);


     long double tgammal(long double x);


DESCRIPTION
     These functions compute the gamma() function of x.

RETURN VALUES
     Upon successful completion, these functions return gamma(x).


     If x is a negative integer, a domain error occurs and a  NaN
     is returned.


     If the correct value would cause  overflow,  a  range  error
     occurs  and  tgamma(),  tgammaf(),  and tgammal() return the
     value of the macro  ]HUGEVAL,  ]HUGEVALF,  or  ]HUGEVAL,
     respectively.


     If x is NaN, a NaN is returned.


     If x is ]Inf, x is returned.


     If x is ]0, a pole error occurs and tgamma(), tgammaf(), and
     tgammal()  return  ]HUGEVAL,  ]HUGEVALF,  and  ]HUGEVAL,
     respectively.


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

ERORS
     These functions will fail if:

     Domain Error    The value of x is a negative integer or x is
                     -Inf.




SunOS 5.11          Last change: 12 Jul 2006                    1






Mathematical Library Functions                         tgamma(3M)



                     If the integer expression  (matherrhandling
                     &  MATHEREXCEPT)  is  non-zero,  then  the
                     invalid floating-point exception is raised.


     Pole Error      The value of x is zero.

                     If the integer expression  (matherrhandling
                     &  MATHEREXCEPT)  is  non-zero,  then  the
                     divide-by-zero floating-point  exception  is
                     raised.


     Range Error     The value overflows.

                     If the integer expression  (matherrhandling
                     &  MATHEREXCEPT)  is  non-zero,  then  the
                     overflow floating-point exception is raised.


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.

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



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


SEE ALSO
     feclearexcept(3M),       fetestexcept(3M),       lgamma(3M),
     math.h(3HEAD), attributes(5), standards(5)








SunOS 5.11          Last change: 12 Jul 2006                    2