|GAMMA(3)||Linux Programmer's Manual||GAMMA(3)|
NAMEgamma, gammaf, gammal - (logarithm of the) gamma function
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCEgammaf(), gammal():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600
DESCRIPTIONThese functions are deprecated: instead, use either the tgamma(3) or the lgamma(3) functions, as appropriate.
*BSD versionThe libm in 4.4BSD and some versions of FreeBSD had a gamma() function that computes the Gamma function, as one would expect.
glibc versionGlibc has a gamma() function that is equivalent to lgamma(3) and computes the natural logarithm of the Gamma function.
RETURN VALUESee lgamma(3).
CONFORMING TOBecause of historical variations in behavior across systems, this function is not specified in any standard.
History4.2BSD had a gamma() that computed ln(|Gamma(| x|)|), leaving the sign of Gamma(| x|) in the external integer signgam. 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"
SEE ALSOlgamma(3), signgam(3), tgamma(3)
COLOPHONThis page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.