Returns the complex arc tangent of its argument.

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

    Format

      #include  <complex.h>

      double complex catan  (double complex z);

      float complex catanf  (float complex z);

      long double complex catanl  (long double complex z);

  Additional Information (explode) :

• Argument
• Description
• Return Values