`msvcrt`

The Python msvcrt module exposes a subset of the Microsoft Visual C++ runtime library on Windows. It provides low-level access to console input, wide-character I/O, file locking, and file-descriptor bridging routines that are otherwise unavailable from cross-platform modules.

This module is only present on Windows, and several higher-level standard library modules, including getpass, rely on it for their Windows-specific code paths.

Here’s a quick example:

>>> import msvcrt

>>> msvcrt.kbhit()
0
>>> msvcrt.getch()
b'a'

The call to kbhit() reports that no key is currently buffered, and getch() blocks until the user presses a key, returning the corresponding byte without echoing it to the console.

Key Features

Reads individual keystrokes without waiting for a newline or echoing to the screen
Polls the console for pending input with kbhit()
Provides wide-character Unicode counterparts for all console I/O functions
Locks and unlocks byte ranges in an open file through locking()
Converts between Python file descriptors and raw Windows HANDLE values
Controls the text or binary translation mode of an open file descriptor with setmode()

Frequently Used Classes and Functions

Object	Type	Description
`msvcrt.kbhit()`	Function	Returns a nonzero value if a keystroke is waiting to be read
`msvcrt.getch()`	Function	Reads a single keypress as a `bytes` object without echoing it
`msvcrt.getche()`	Function	Reads a single keypress and echoes it to the console
`msvcrt.getwch()`	Function	Reads a single keypress as a Unicode character without echoing it
`msvcrt.putch()`	Function	Writes a single byte to the console without buffering
`msvcrt.putwch()`	Function	Writes a single Unicode character to the console without buffering
`msvcrt.ungetch()`	Function	Pushes a byte back into the console input buffer
`msvcrt.locking()`	Function	Locks or unlocks a byte range in an open file
`msvcrt.setmode()`	Function	Switches a file descriptor between text and binary translation modes
`msvcrt.get_osfhandle()`	Function	Returns the underlying Windows handle for a given file descriptor
`msvcrt.open_osfhandle()`	Function	Wraps a raw Windows handle in a C runtime file descriptor

Examples

Reading a single keystroke without echo from the console:

>>> import msvcrt

>>> key = msvcrt.getch()
>>> key
b'q'

Polling for input inside a non-blocking loop:

import msvcrt
import time

print("Press any key to stop...")
while not msvcrt.kbhit():
    print("working", end="\r", flush=True)
    time.sleep(0.5)

print(f"\nPressed: {msvcrt.getch()!r}")

Reading a wide character to support non-ASCII input:

>>> import msvcrt

>>> msvcrt.getwch()
'n'

Locking a byte range in an open file with locking():

import msvcrt

with open("data.txt", "r+b") as fp:
    fd = fp.fileno()
    msvcrt.locking(fd, msvcrt.LK_NBLCK, 100)
    try:
        fp.write(b"updated region")
    finally:
        fp.seek(0)
        msvcrt.locking(fd, msvcrt.LK_UNLCK, 100)

The LK_NBLCK flag attempts the lock without blocking and raises OSError if another process already holds it, while LK_LOCK retries up to ten times at one-second intervals.

Obtaining the raw Windows handle for a file descriptor:

>>> import msvcrt

>>> import sys
>>> msvcrt.get_osfhandle(sys.stdout.fileno())
7

Common Use Cases

The most common tasks for msvcrt include:

Implementing Windows-friendly password prompts that hide characters as the user types
Building interactive command-line programs that react to single keystrokes
Polling for user input without blocking a running animation or progress display
Coordinating concurrent writers by locking byte ranges in a shared data file
Interoperating with Windows APIs that require a raw HANDLE rather than a Python file object

Real-World Example

Consider a tiny Windows password prompt that reads characters one at a time, displays an asterisk for each keystroke, and stops when the user presses Enter. The msvcrt module provides every piece needed to build it, from getwch() for wide-character input to putwch() for immediate echo:

import msvcrt

def prompt_password(label="Password: "):
    print(label, end="", flush=True)
    buffer = []
    while True:
        char = msvcrt.getwch()
        if char in ("\r", "\n"):
            msvcrt.putwch("\n")
            return "".join(buffer)
        if char == "\x03":
            raise KeyboardInterrupt
        if char == "\b":
            if buffer:
                buffer.pop()
                msvcrt.putwch("\b")
                msvcrt.putwch(" ")
                msvcrt.putwch("\b")
            continue
        buffer.append(char)
        msvcrt.putwch("*")

if __name__ == "__main__":
    secret = prompt_password()
    print(f"Captured {len(secret)} characters.")

Run the script from a Windows command prompt:

PS> python prompt_password.py
Password: ********
Captured 8 characters.

When the script runs in a Windows console, each keystroke is captured instantly without being echoed by the terminal. The helper shows a masked asterisk, handles backspace by erasing the last character on screen, and returns the assembled string once Enter is pressed. This is the same general approach used by getpass.getpass() when it runs on Windows.

Tutorial

How to Read User Input From the Keyboard in Python

Reading user input from the keyboard is a valuable skill for a Python programmer, and you can create interactive and advanced programs that run on the terminal. In this tutorial, you'll learn how to create robust user input programs, integrating error handling and multiple entries.

basics best-practices

For additional information on related topics, take a look at the following resources: