GAMMA(3M)

NAME
gamma - log gamma function

SYNOPSIS
#include <math.h>

double gamma(x)
double x;

DESCRIPTION
Gamma returns ln |Γ(|x|)|. The sign of Γ(|x|) is returned in the external integer signgam. The following C program might be used to calculate Γ:

    y = gamma(x);
    if (y > 88.)
        error( );
    y = exp(y);
    if(signgam)
        y = -y;

DIAGNOSTICS
A huge value is returned for negative integer arguments.

BUGS
There should be a positive indication of error.