Issue #4254: Adds _curses.update_lines_cols() Patch by Arnon Yaari

Doc/library/curses.rst

@@ -599,6 +599,13 @@ The module :mod:`curses` defines the following functions:
       Only one *ch* can be pushed before :meth:`getch` is called.
 
 
+.. function:: update_lines_cols()
+
+   Update :envvar:`LINES` and :envvar:`COLS`. Useful for detecting manual screen resize.
+
+   .. versionadded:: 3.5
+
+
 .. function:: unget_wch(ch)
 
    Push *ch* so the next :meth:`get_wch` will return it.

Doc/whatsnew/3.5.rst

@@ -289,6 +289,11 @@ contextlib
   don't provide any options to redirect it.
   (Contributed by Berker Peksag in :issue:`22389`.)
 
+curses
+------
+* The new :func:`curses.update_lines_cols` function updates the variables
+  :envvar:`curses.LINES` and :envvar:`curses.COLS`.
+
 difflib
 -------
 

Lib/test/test_curses.py

@@ -370,6 +370,13 @@ class TestCurses(unittest.TestCase):
         offset = human_readable_signature.find("[y, x,]")
         assert offset >= 0, ""
 
+    def test_update_lines_cols(self):
+        # this doesn't actually test that LINES and COLS are updated,
+        # because we can't automate changing them. See Issue #4254 for
+        # a manual test script. We can only test that the function
+        # can be called.
+        curses.update_lines_cols()
+
 
 if __name__ == '__main__':
     unittest.main()

Misc/NEWS

@@ -36,6 +36,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #4254: Adds _curses.update_lines_cols() Patch by Arnon Yaari
+
 - Issue 19933: Provide default argument for ndigits in round. Patch by
   Vajrasky Kok.
 

Modules/_cursesmodule.c

@@ -2866,6 +2866,13 @@ update_lines_cols(void)
     Py_DECREF(m);
     return 1;
 }
+
+static PyObject *
+PyCurses_update_lines_cols(PyObject *self)
+{
+  return PyLong_FromLong((long) update_lines_cols());
+}
+
 #endif
 
 #ifdef HAVE_CURSES_RESIZETERM
@@ -3268,6 +3275,9 @@ static PyMethodDef PyCurses_methods[] = {
     {"typeahead",           (PyCFunction)PyCurses_TypeAhead, METH_VARARGS},
     {"unctrl",              (PyCFunction)PyCurses_UnCtrl, METH_VARARGS},
     {"ungetch",             (PyCFunction)PyCurses_UngetCh, METH_VARARGS},
+#if defined(HAVE_CURSES_RESIZETERM) || defined(HAVE_CURSES_RESIZE_TERM)
+    {"update_lines_cols",   (PyCFunction)PyCurses_update_lines_cols, METH_NOARGS},
+#endif
 #ifdef HAVE_NCURSESW
     {"unget_wch",           (PyCFunction)PyCurses_Unget_Wch, METH_VARARGS},
 #endif