Returns the gamma function of its argument.

    This function is supported on OpenVMS Integrity servers and
    Alpha only.

    Format

      #include  <math.h>

      double tgamma  (double x);

      float tgammaf  (float x);

      long double tgammal  (long double x);

1  –  Argument

 x

    A real value.

2  –  Description

    The tgamma functions compute the gamma function of x.

3  –  Return Values

    n                  Upon success, the gamma function of x.
    -1                 If x is negative. errno is set to EDOM.
    HUGE_VAL           Overflow occurred, or x is 0. errno is set to
                       ERANGE.
    NaN                If x is NaN or -Inf. errno is set to EDOM.
    x                  If x is +Inf.