Guardian Native C Library Calls Reference Manual (G06.29+, H06.08+, J06.03+)

tgamma(3) Guardian Native C Library Calls Reference Manual
NAME
tgamma - Computes the true gamma function
LIBRARY
H-series and J-series native Guardian processes: $SYSTEM.ZDLLnnn.ZCREDLL
32-bit H-series and J-series OSS processes: /G/system/zdllnnn/zcredll
64-bit H-series and J-series OSS processes: /G/system/zdllnnn/ycredll
SYNOPSIS
#include <math.h>
double tgamma(
double x);
PARAMETERS
x Specifies a positive double value.
DESCRIPTION
The tgamma() function computes the true gamma function of x. In contrast, the lgamma()
function and the gamma() function compute the logarithm of gamma.
NOTES
This function is implemented only for the IEEE_float floating-point option. Applications using
this function cannot be compiled if the specified floating-point option is Tandem_float.
RETURN VALUES
Upon successful completion, the tgamma() function returns the true gamma of x.
If the value of x is a negative integer, NaN is returned and errno is set to [EDOM].
If the value of x is NaN, NaN is returned.
If the value of x is positive infinity, x is returned.
If the value of x is negative infinity, NaN is returned and errno is set to [EDOM].
If the value of x is positive or negative zero, HUGE_VAL is returned and errno is set to
[ERANGE]
If the result would cause overflow, +HUGE_VAL or -HUGE_VAL (with the same sign as the
correct value of the function) is returned and errno is set to [ERANGE].
ERRORS
If any of the following conditions occurs, the tgamma() function sets errno to the corresponding
value:
[EDOM] The value of x is a negative integer or negative infinity.
[ERANGE] The value to be returned is positive or negative zero or would cause overflow.
RELATED INFORMATION
Functions: exp(3), lgamma(3), log(3), tgammaf(3), tgammal(3).
Files: math(4).
STANDARDS CONFORMANCE
This function conforms to the ISO/IEC 9899:1999 standard.
This function conforms to the IEEE Std 1003.1, 2004 Edition.
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