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GAMMA(3) Linux Programmer's Manual GAMMA(3)NAMEgamma, gammaf, gammal - (logarithm of the) gamma functionSYNOPSIS#include<math.h>doublegamma(doublex);floatgammaf(floatx);longdoublegammal(longdoublex);Link with-lm. Feature Test Macro Requirements for glibc (see feature_test_macros(7)):gamma(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCEgammaf(),gammal(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600DESCRIPTIONThese functions are deprecated: instead, use either the tgamma(3) or the lgamma(3) functions, as appropriate. For the definition of the Gamma function, see tgamma(3).*BSDversionThe libm in 4.4BSD and some versions of FreeBSD had agamma() function that computes the Gamma function, as one would expect.glibcversionGlibc has agamma() function that is equivalent to lgamma(3) and computes the natural logarithm of the Gamma function.RETURNVALUESee lgamma(3).ERRORSSee lgamma(3).CONFORMINGTOBecause of historical variations in behavior across systems, this function is not specified in any standard.NOTESHistory4.2BSD had agamma() that computed ln(|Gamma(|x|)|), leaving the sign of Gamma(|x|) in the external integersigngam. In 4.3BSD the name was changed to lgamma(3), 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, wheregamma() computes the Gamma function (with no effect onsigngam). How- ever, this came too late, and we now have tgamma(3), the "true gamma" function.SEEALSOlgamma(3), signgam(3), tgamma(3)COLOPHONThis page is part of release 3.22 of the Linuxman-pagesproject. A description of the project, and informa- tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. GNU 2008-08-05 GAMMA(3)