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 > 706.0)
error();
y = exp(y);
if(signgam)
y = −y;

Note that exp for arguments greater than 706.0 produce an infinite result in IEEE double-precision floating-point format. 

DIAGNOSTICS

A huge value is returned for negative integer arguments. 

BUGS

There should be a positive indication of error. 

Sun System Release 0.3  —  26 April 1983