curses.filter can not be used as described in its documentation

[robinbryce]

BPO	1940
Nosy	@birkenfeld

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2008-01-26.14:04:35.516>
created_at = <Date 2008-01-26.12:56:45.799>
labels = ['type-bug', 'library', 'docs']
title = 'curses.filter can not be used as described in its documentation'
updated_at = <Date 2008-01-26.14:04:35.505>
user = 'https://bugs.python.org/robinbryce'

bugs.python.org fields:

activity = <Date 2008-01-26.14:04:35.505>
actor = 'georg.brandl'
assignee = 'none'
closed = True
closed_date = <Date 2008-01-26.14:04:35.516>
closer = 'georg.brandl'
components = ['Documentation', 'Library (Lib)']
creation = <Date 2008-01-26.12:56:45.799>
creator = 'robinbryce'
dependencies = []
files = []
hgrepos = []
issue_num = 1940
keywords = []
message_count = 2.0
messages = ['61708', '61709']
nosy_count = 2.0
nosy_names = ['georg.brandl', 'robinbryce']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue1940'
versions = ['Python 2.5']

[robinbryce]

curses.filter forces the top most window to 1 line tall and preserves
existing tty content. It must be called *before* curses.initscr in order
to acheive this.

The python documentation states that curses.filter must be called before
initscr but the implementation prevents this. It uses the
NoArgNoReturnVoidFunction macro defined in Include/py_curses.h. This
macro in turn invokes the PyCursesInitialised macro which forces an
error if initscr has not been called.

curses.filter needs an explicit definition to avoid this:

Replacing "NoArgNoReturnVoidFunction(filter)" in Modules/_cursesmodule.c
with

static PyObject *PyCurses_filter (PyObject *self)
{
  /* MUST NOT BE PyCursesInitialised */
  filter(); \
  Py_INCREF(Py_None);
  return Py_None;
}

Would allow curses.filter to be called as documented. But really should
get a check for "!PyCursesInitialised".

[birkenfeld]

You're right. I fixed this in r60322, r60323 (2.5).