catan

   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 available:

Argument        Description     Return_Values