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gamma(3) - gamma, gammaf, gammal, gamma, gammaf, gammal - (logarithm of the) gamma function - man 3 gamma

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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);

       Link with -lm.

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


   *BSD version(1,3,5)
       4.4BSD and FreeBSD libm have a gamma() function that computes the Gamma
       function, as one would expect.

   glibc version(1,3,5)
       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(1,8) the external integer signgam.  In 4.3BSD the name was
       changed to lgamma(), and the man(1,5,7) page promises

          "At some time(1,2,n) in(1,8) the future the name gamma will be rehabilitated and
          used for the Gamma function"

       This  did  indeed  happen  in(1,8)  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)

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