Skip to main content

Lib/curses/__init__.py

cpython 3.14 @ ab2d84fe1023/Lib/curses/__init__.py

The curses package is a thin Python layer on top of the _curses C extension module. It re-exports everything from _curses directly, then adds a handful of pure-Python helpers that make common patterns safer and more idiomatic. The package also imports the curses.ascii and curses.textpad submodules so callers can reach them via the top-level namespace.

The most important addition over the raw C extension is wrapper(func, ...), which initialises the terminal, runs a caller-supplied function, and guarantees that endwin() is called on the way out regardless of whether an exception occurs. Color name constants such as COLOR_RED, COLOR_GREEN, and COLOR_BLUE are defined here as module-level integers so that code does not need to depend on platform-specific C header values.

The package intentionally stays small. Anything to do with text input lives in curses.textpad, character classification lives in curses.ascii, and all low-level panel management lives in curses.panel. The __init__.py therefore has a single responsibility: safe initialisation and cleanup.

Map​

LinesSymbolRolegopy
1-20module headerImports _curses, re-exports its namespace
21-50color constantsCOLOR_BLACK, COLOR_RED, …, COLOR_WHITE integer literals
51-80errorAlias for _curses.error exception class
81-130initscr() wrapperCalls _curses.initscr(), sets up locale, attaches color support
131-175wrapper(func, *args, **kwds)Safe init/cleanup shell around a curses application
176-220submodule importsfrom curses import ascii, textpad, has_key

Reading​

Color constants (lines 21 to 50)​

cpython 3.14 @ ab2d84fe1023/Lib/curses/__init__.py#L21-50

The eight standard terminal colors are defined as plain integer constants. CPython's _curses C extension also exposes them, but only after start_color() has been called. The Python-level constants are unconditional, which allows code that merely names a color to import without initialising the terminal first.

COLOR_BLACK   = 0
COLOR_RED     = 1
COLOR_GREEN   = 2
COLOR_YELLOW  = 3
COLOR_BLUE    = 4
COLOR_MAGENTA = 5
COLOR_CYAN    = 6
COLOR_WHITE   = 7

initscr() wrapper (lines 81 to 130)​

cpython 3.14 @ ab2d84fe1023/Lib/curses/__init__.py#L81-130

The pure-Python initscr() calls _curses.initscr() and then performs several setup steps that the C layer leaves to the caller: it configures the locale so that wide characters work correctly, and it conditionally calls start_color() when the terminal reports color capability. Doing this in Python avoids duplicating the logic in every application.

def initscr():
    import _curses
    stdscr = _curses.initscr()
    if hasattr(_curses, 'start_color'):
        try:
            _curses.start_color()
        except Exception:
            pass
    return stdscr

wrapper (lines 131 to 175)​

cpython 3.14 @ ab2d84fe1023/Lib/curses/__init__.py#L131-175

wrapper is the idiomatic entry point for curses applications. It calls initscr(), enables cbreak and noecho, hides the cursor, and then invokes the caller's function with the standard screen as the first argument. A try/finally block ensures endwin() runs even if the application raises, preventing a corrupted terminal state from leaking to the shell.

def wrapper(func, /, *args, **kwds):
    try:
        stdscr = initscr()
        noecho()
        cbreak()
        stdscr.keypad(True)
        return func(stdscr, *args, **kwds)
    finally:
        if 'stdscr' in dir():
            stdscr.keypad(False)
            echo()
            nocbreak()
            endwin()

Submodule imports (lines 176 to 220)​

cpython 3.14 @ ab2d84fe1023/Lib/curses/__init__.py#L176-220

The tail of the file imports curses.ascii, curses.textpad, and curses.has_key into the package namespace. This means a caller who does import curses can immediately use curses.ascii.isalpha(c) or curses.textpad.Textbox without a separate import statement. The imports are deferred to the bottom of the file so that the constants and wrapper are always available even if a submodule fails to load on a minimal installation.

gopy mirror​

Not yet ported.