# `msvcrt` — Useful routines from the MS VC++ runtime

Source code: PC/msvcrtmodule.c

These functions provide access to some useful capabilities on Windows platforms. Some higher-level modules use these functions to build the Windows implementations of their services. For example, the `getpass` module uses this in the implementation of the `getpass()` function.

Más información sobre estas funciones se pueden encontrar en la documentación de la API de la plataforma.

El módulo implementa las variantes tanto de caracteres normales como amplios de la API E/S de la consola (se codifican en más de 8 bits, pudiendo llegar hasta 32). La API normal se ocupa solamente de caracteres ASCII y es de uso limitado a aplicaciones internacionales. La API para caracteres amplios se recomienda usar siempre que sea posible.

Availability: Windows.

Distinto en la versión 3.3: Las operaciones en este módulo lanzan ahora `OSError` donde antes se lanzaba `IOError`.

## Operaciones con archivos

msvcrt.locking(fd, mode, nbytes)

  Lock part of a file based on file descriptor fd from the C runtime. Raises `OSError` on failure. The locked region of the file extends from the current file position for nbytes bytes, and may continue beyond the end of the file. mode must be one of the `LK_*` constants listed below. Multiple regions in a file may be locked at the same time, but may not overlap. Adjacent regions are not merged; they must be unlocked individually.

  Lanza un evento de auditoría `msvcrt.locking` con los argumentos `fd`, `mode`, `nbytes`.

msvcrt.LK_LOCK
msvcrt.LK_RLCK

  Locks the specified bytes. If the bytes cannot be locked, the program immediately tries again after 1 second. If, after 10 attempts, the bytes cannot be locked, `OSError` is raised.

msvcrt.LK_NBLCK
msvcrt.LK_NBRLCK

  Bloquea los bytes especificados. Si no se pueden bloquear, lanza una excepción `OSError`.

msvcrt.LK_UNLCK

  Desbloquea los bytes especificados que han sido previamente bloqueados.

msvcrt.setmode(fd, flags)

  Establece el modo traducción del final de línea del descriptor de un archivo fd. Si se establece como modo texto, flags debería ser `os.O_TEXT`; para establecerlo como modo binario, debería ser `os.O_BINARY`.

msvcrt.open_osfhandle(handle, flags)

  Create a C runtime file descriptor from the file handle handle. The flags parameter should be a bitwise OR of `os.O_APPEND`, `os.O_RDONLY`, `os.O_TEXT` and `os.O_NOINHERIT`. The returned file descriptor may be used as a parameter to `os.fdopen()` to create a file object.

  The file descriptor is inheritable by default. Pass `os.O_NOINHERIT` flag to make it non inheritable.

  Lanza un evento de auditoría `msvcrt.open_osfhandle` con los argumentos `handle`, `flags`.

msvcrt.get_osfhandle(fd)

  Return the file handle for the file descriptor fd. Raises `OSError` if fd is not recognized.

  Lanza un evento de auditoría `msvcrt.get_osfhandle` con el argumento `fd`.

## Consola E/S

msvcrt.kbhit()

  Returns a nonzero value if a keypress is waiting to be read. Otherwise, return 0.

msvcrt.getch()

  Read a keypress and return the resulting character as a byte string. Nothing is echoed to the console. This call will block if a keypress is not already available, but will not wait for `Enter` to be pressed. If the pressed key was a special function key, this will return `'\000'` or `'\xe0'`; the next call will return the keycode. The `Control`-`C` keypress cannot be read with this function.

msvcrt.getwch()

  Variante de carácter amplio de `getch()`, retornando un valor Unicode.

msvcrt.getche()

  Similar to `getch()`, but the keypress will be echoed if it represents a printable character.

msvcrt.getwche()

  Variante de carácter amplio de `getche()`, retornando un valor Unicode.

msvcrt.putch(char)

  Print the byte string char to the console without buffering. Raises `OSError` on failure, for example when the process has no console attached.

  Distinto en la versión 3.16.0a0 (unreleased): Failures are now reported by raising `OSError` instead of being silently ignored.

msvcrt.putwch(unicode_char)

  Variante de carácter amplio de `putch()`, admitiendo un valor Unicode.

  Distinto en la versión 3.16.0a0 (unreleased): Failures are now reported by raising `OSError` instead of being silently ignored.

msvcrt.ungetch(char)

  Provoca que la cadena de caracteres de bytes char sea «colocada de nuevo» en el buffer de la consola, será el siguiente carácter que lea la función `getch()` o `getche()`.

msvcrt.ungetwch(unicode_char)

  Variante de carácter amplio de `ungetch()`, admitiendo un valor Unicode.

## Otras funciones

msvcrt.heapmin()

  Force the `malloc()` heap to clean itself up and return unused blocks to the operating system. On failure, this raises `OSError`.

msvcrt.set_error_mode(mode)

  Changes the location where the C runtime writes an error message for an error that might end the program. mode must be one of the `OUT_*` constants listed below or `REPORT_ERRMODE`. Returns the old setting or -1 if an error occurs. Only available in debug build of Python.

msvcrt.OUT_TO_DEFAULT

  Error sink is determined by the app’s type. Only available in debug build of Python.

msvcrt.OUT_TO_STDERR

  Error sink is a standard error. Only available in debug build of Python.

msvcrt.OUT_TO_MSGBOX

  Error sink is a message box. Only available in debug build of Python.

msvcrt.REPORT_ERRMODE

  Report the current error mode value. Only available in debug build of Python.

msvcrt.CrtSetReportMode(type, mode)

  Specifies the destination or destinations for a specific report type generated by `_CrtDbgReport()` in the MS VC++ runtime. type must be one of the `CRT_*` constants listed below. mode must be one of the `CRTDBG_*` constants listed below. Only available in debug build of Python.

msvcrt.CrtSetReportFile(type, file)

  After you use `CrtSetReportMode()` to specify `CRTDBG_MODE_FILE`, you can specify the file handle to receive the message text. type must be one of the `CRT_*` constants listed below. file should be the file handle your want specified. Only available in debug build of Python.

msvcrt.CRT_WARN

  Warnings, messages, and information that doesn’t need immediate attention.

msvcrt.CRT_ERROR

  Errors, unrecoverable problems, and issues that require immediate attention.

msvcrt.CRT_ASSERT

  Assertion failures.

msvcrt.CRTDBG_MODE_DEBUG

  Writes the message to the debugger’s output window.

msvcrt.CRTDBG_MODE_FILE

  Writes the message to a user-supplied file handle. `CrtSetReportFile()` should be called to define the specific file or stream to use as the destination.

msvcrt.CRTDBG_MODE_WNDW

  Creates a message box to display the message along with the `Abort`, `Retry`, and `Ignore` buttons.

msvcrt.CRTDBG_REPORT_MODE

  Returns current mode for the specified type.

msvcrt.CRT_ASSEMBLY_VERSION

  The CRT Assembly version, from the `crtassem.h` header file.

msvcrt.VC_ASSEMBLY_PUBLICKEYTOKEN

  The VC Assembly public key token, from the `crtassem.h` header file.

msvcrt.LIBRARIES_ASSEMBLY_NAME_PREFIX

  The Libraries Assembly name prefix, from the `crtassem.h` header file.