Section (3) gamma
gamma, gammaf, gammal — (logarithm of the) gamma function
||long double x
For the definition of the Gamma function, see tgamma(3).
The libm in 4.4BSD and some versions of FreeBSD had a
gamma() function that
computes the Gamma function, as one would expect.
Glibc has a
function that is equivalent to lgamma(3) and computes
the natural logarithm of the Gamma function.
For an explanation of the terms used in this section, see attributes(7).
||Thread safety||MT-Unsafe race:signgam|
Because of historical variations in behavior across systems, this function is not specified in any recent standard. It was documented in SVID 2.
4.2BSD had a
x|)|), leaving the sign of
x|) in the
4.3BSD the name was changed to lgamma(3), and the man
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, where
gamma() computes the Gamma function (with
no effect on
However, this came too late, and we now have tgamma(3), the true
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Copyright 2002 Walter Harms (walter.harmsinformatik.uni-oldenburg.de)
Distributed under GPL
Modified 2003-11-18, aeb: historical remarks