HP-UX Reference (11i v2 04/09) - 3 Library Functions A-M (vol 6)

lgamma(3M) lgamma(3M)

lgammaq(), gammaq(), and lgammaq_r are equivalent to

lgammal(), gammal(), and

lgammal_r() respectively on HP-UX systems.

USAGE

To use these functions, compile either with the default

-Ae option or with the -Aa and

-D_HPUX_SOURCE

options.

To use (for Itanium-based systems)

lgammaw(), lgammaw_r(), gammaw(), lgammaq()

lgammaq_r(),orgammaq(), compile also with the

-fpwidetypes option.

Make sure your program includes

<math.h>, and link in the math library by specifying

-lm on the com-

piler or linker command line.

For more information, see the HP-UX Floating-Point Guide.

RETURN VALUE

lgamma(1) returns +0.

lgamma(2) returns +0.

lgamma(x) returns +Inf and raises the divide-by- zero ﬂoating-point exception for x a negative integer

or zero.

lgamma(-Inf) returns +Inf.

lgamma(+Inf) returns +Inf.

If x is NaN,

lgamma() and gamma() return NaN.

lgamma() returns inﬁnity (equal to HUGE_VAL) in lieu of a value whose magnitude is too large, and

raises the overﬂow and inexact exceptions.

When it raises no other exception, whether

lgamma() raises the inexact exception is unspeciﬁed.

WARNINGS

lgamma() and gamma() are unsafe in multi-thread applications.

lgamma_r() is MT-Safe and should

be used instead.