gammaf

GAMMA(3)		     libc math functions		     GAMMA(3)



NAME
       gamma, gammaf, gammal - (logarithm of the) gamma function

SYNOPSIS
       #include <math.h>

       double gamma(double x);

       float gammaf(float x);

       long double gammal(long double x);


DESCRIPTION
       For the definition of the Gamma function, see tgamma(3).


   *BSD version
       4.4BSD  and  FreeBSD  libm  have	 a gamma() function that computes the
       Gamma function, as one would expect.

   glibc version
       Glibc has a gamma() function that is equivalent to lgamma()  and	 com-
       putes  the natural logarithm of the Gamma function.  (This is for com-
       patibility reasons only. Don’t use this function.)

HISTORY
       4.2BSD had a gamma() that computed ln(|Gamma(|x|)|), leaving the	 sign
       of Gamma(|x|) in the external integer signgam.  In 4.3BSD the name was
       changed to lgamma(), and the man page promises

	  "At some time in the future the name gamma  will  be	rehabilitated
	  and used for the Gamma function"

       This  did  indeed  happen  in 4.4BSD, where gamma() computes the Gamma
       function (with no effect on signgam).  However, this  came  too	late,
       and we now have tgamma(), the "true gamma" function.

CONFORMING TO
       4.2BSD. Compatible with previous mistakes.

SEE ALSO
       lgamma(3), signgam(3), tgamma(3)



GNU				  2002-08-10			     GAMMA(3)