osf1 man page for gamma

lgamma(3)						     Library Functions Manual							 lgamma(3)

NAME
       lgamma, gamma - Compute the logarithm of the gamma function

LIBRARY
       Math Library (libm.a)

SYNOPSIS
       #include <math.h>

       double lgamma  (double x); float  lgammaf (float  x); long double lgammal  (long double x);

STANDARDS
       Interfaces documented on this reference page conform to industry standards as follows:

       lgamma():  XPG4

       gamma():  XPG4

       Refer to the standards(5) reference page for more information about industry standards and associated tags.

DESCRIPTION
       The  lgamma(),  lgammaf(),  and lgammal() functions return the logarithm of the absolute value of gamma of x, or ln(|G(x)|), where G is the
       gamma function. The sign of gamma of x is returned in the external integer variable signgam.  The x parameter cannot be	0  or  a  negative
       integer.

       The gamma() function returns the natural log of the gamma function and so is functionally equivalent to lgamma().  Because of this, gamma()
       is marked TO BE WITHDRAWN in the X/Open Portability Guide, Revision 4 (XPG4).

       The following table describes function behavior in response to exceptional arguments:

       -------------------------------------------------------------------------
       Function 		       Exceptional Argument    Routine Behavior
       -------------------------------------------------------------------------
       lgamma(), lgammaf(), lgamma()   |x| = infinity	       Invalid argument
       lgamma(), lgammaf(), lgamma()   x = 0, -1, -2, -3,...   Invalid argument
       lgamma(), lgammaf(), lgamma()   x > lgamma_max_float    Overflow
       -------------------------------------------------------------------------

       The following table lists boundary values used by these functions:

       -------------------------------------------------------------------------
       Value		  Data	     Hexadecimal Value	 Decimal Value
       Name		  Type
       -------------------------------------------------------------------------
       lgamma_max_float   S_FLOAT    7BC650F9		 2.0594342e36
			  T_FLOAT    7F475ABDC501F55F	 1.2812545499066958e305
       -------------------------------------------------------------------------
       delim off

																	 lgamma(3)