copy from scripts/specfun/gammai.m
copy to scripts/deprecated/gammai.m
--- a/scripts/specfun/gammai.m
+++ b/scripts/deprecated/gammai.m
@@ -22,14 +22,22 @@
 ## This function is provided for compatibility with older versions of
 ## Octave.  New programs should use @code{gammainc} instead.
 ##
-## @code{gammai (@var{a}, @var{x})} is the same as @code{gammainc
-## (@var{x}, @var{a})}.
+## @code{gammai (@var{a}, @var{x})} is the same as 
+## @code{gammainc (@var{x}, @var{a})}.
 ## @end deftypefn
 
 ## Author: jwe
 ## Created: 30 Jan 1998
 
+## Deprecated in version 3.4
+
 function retval = gammai (a, x)
+  persistent warned = false;
+  if (! warned)
+    warned = true;
+    warning ("Octave:deprecated-function",
+             "gammai is obsolete and will be removed from a future version of Octave; please use gammainc instead");
+  endif
 
   if (nargin == 2)
     retval = gammainc (x, a);