Content-type: text/html Man page of tgamma

# tgamma

Section: Mathematical Library Functions (3M)
Updated: 12 Jul 2006
Index Return to Main Contents

## NAME

tgamma, tgammaf, tgammal - compute gamma function

## SYNOPSIS

c99 [ flag... ] file... -lm [ library... ]
#include <math.h>

double tgamma(double x);

float tgammaf(float x);

long double tgammal(long double x);

## DESCRIPTION

These functions compute the gamma() function of x.

## RETURN VALUES

Upon successful completion, these functions return gamma(x).

If x is a negative integer, a domain error occurs and a NaN is returned.

If the correct value would cause overflow, a range error occurs and tgamma(), tgammaf(), and tgammal() return the value of the macro ±HUGE_VAL, ±HUGE_VALF, or ±HUGE_VALL, respectively.

If x is NaN, a NaN is returned.

If x is ±Inf, x is returned.

If x is ±0, a pole error occurs and tgamma(), tgammaf(), and tgammal() return ±HUGE_VAL, ±HUGE_VALF, and ±HUGE_VALL, respectively.

If x is +Inf, a domain error occurs and a NaN is returned.

## ERRORS

These functions will fail if:

Domain Error The value of x is a negative integer or x is -Inf.

If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception is raised.

Pole Error The value of x is zero.

If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the divide-by-zero floating-point exception is raised.

Range Error The value overflows.

If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point exception is raised.

## USAGE

An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.

## ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

 ATTRIBUTE TYPE ATTRIBUTE VALUE Interface Stability Standard MT-Level MT-Safe

## SEE ALSO

feclearexcept(3M), fetestexcept(3M), lgamma(3M), math.h(3HEAD), attributes(5), standards(5)

## Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUES
ERRORS
USAGE
ATTRIBUTES
SEE ALSO

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Time: 02:39:33 GMT, October 02, 2010