bpo-36982: Add support for extended color functions in ncurses 6.1

Doc/library/curses.rst

@@ -242,6 +242,16 @@ The module :mod:`curses` defines the following functions:
 
    Return ``True`` if the terminal can display colors; otherwise, return ``False``.
 
+.. function:: has_extended_color_support()
+
+   Return ``True`` if the module supports extended colors; otherwise, return
+   ``False``. Extended color support allows more than 256 color-pairs for
+   terminals that support more than 16 colors (e.g. xterm-256color).
+
+   Extended color support requires ncurses version 6.1 or later.
+
+   .. versionadded:: 3.8
+
 
 .. function:: has_ic()
 

Doc/whatsnew/3.8.rst

@@ -346,6 +346,21 @@ where the DLL is stored (if a full or partial path is used to load the initial
 DLL) and paths added by :func:`~os.add_dll_directory`.
 
 
+curses
+-------
+
+Added a new variable holding structured version information for the
+underlying ncurses library: :data:`~curses.ncurses_version`.
+(Contributed by Serhiy Storchaka in :issue:`31680`.)
+
+The extended color functions added in ncurses 6.1 will be used transparently
+by :func:`curses.color_content`, :func:`curses.init_color`,
+:func:`curses.init_pair`, and :func:`curses.pair_content`. A new function,
+:func:`curses.has_extended_color_support`, indicates whether extended color
+support is provided by the underlying ncurses library.
+(Contributed by Jeffrey Kintscher in :issue:`36982`.)
+
+
 functools
 ---------
 
@@ -503,14 +518,6 @@ environment variable and does not use :envvar:`HOME`, which is not normally set
 for regular user accounts.
 
 
-ncurses
--------
-
-Added a new variable holding structured version information for the
-underlying ncurses library: :data:`~curses.ncurses_version`.
-(Contributed by Serhiy Storchaka in :issue:`31680`.)
-
-
 pathlib
 -------
 

Lib/test/test_curses.py

@@ -231,7 +231,8 @@ def test_module_funcs(self):
                      curses.nocbreak, curses.noecho, curses.nonl,
                      curses.noqiflush, curses.noraw,
                      curses.reset_prog_mode, curses.termattrs,
-                     curses.termname, curses.erasechar]:
+                     curses.termname, curses.erasechar,
+                     curses.has_extended_color_support]:
             with self.subTest(func=func.__qualname__):
                 func()
         if hasattr(curses, 'filter'):

Misc/NEWS.d/next/Core and Builtins/2019-05-25-05-27-39.bpo-36982.0UHgfB.rst

@@ -0,0 +1 @@
+Use ncurses extended color functions when available to support terminals with 256 colors, and add the new function :func:`curses.has_extended_color_support` to indicate whether extended color support is provided by the underlying ncurses library.