tgammal(3m) - osol9

1tgamma(3M)              Mathematical Library Functions              tgamma(3M)
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NAME

6       tgamma, tgammaf, tgammal - compute gamma function
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SYNOPSIS

9       c99 [ flag... ] file... -lm [ library... ]
10       #include <math.h>
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12       double tgamma(double x);
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15       float tgammaf(float x);
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18       long double tgammal(long double x);
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DESCRIPTION

22       These functions compute the gamma() function of x.
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RETURN VALUES

25       Upon successful completion, these functions return gamma(x).
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28       If  x  is  a  negative  integer,  a  domain  error  occurs and a NaN is
29       returned.
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32       If the correct value would cause overflow, a  range  error  occurs  and
33       tgamma(),  tgammaf(),  and  tgammal()  return  the  value  of the macro
34       ±HUGE_VAL, ±HUGE_VALF, or ±HUGE_VALL, respectively.
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37       If x is NaN, a NaN is returned.
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40       If x is ±Inf, x is returned.
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43       If x is ±0, a pole error occurs and tgamma(), tgammaf(), and  tgammal()
44       return ±HUGE_VAL, ±HUGE_VALF, and ±HUGE_VALL, respectively.
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47       If x is +Inf, a domain error occurs and a NaN is returned.
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ERRORS

50       These functions will fail if:
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52       Domain Error    The value of x is a negative integer or x is −Inf.
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54                       If   the   integer   expression   (math_errhandling   &
55                       MATH_ERREXCEPT) is non-zero, then the invalid floating-
56                       point exception is raised.
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59       Pole Error      The value of x is zero.
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61                       If   the   integer   expression   (math_errhandling   &
62                       MATH_ERREXCEPT) is non-zero,  then  the  divide-by-zero
63                       floating-point exception is raised.
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66       Range Error     The value overflows.
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68                       If   the   integer   expression   (math_errhandling   &
69                       MATH_ERREXCEPT) is non-zero, then the  overflow  float‐
70                       ing-point exception is raised.
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USAGE

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

82       See attributes(5) for descriptions of the following attributes:
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87       ┌─────────────────────────────┬─────────────────────────────┐
88       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
89       ├─────────────────────────────┼─────────────────────────────┤
90       │Interface Stability          │Standard                     │
91       ├─────────────────────────────┼─────────────────────────────┤
92       │MT-Level                     │MT-Safe                      │
93       └─────────────────────────────┴─────────────────────────────┘
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