msvcrt —- Useful routines from the MS VC++ runtime

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

Further documentation on these functions can be found in the Platform APIdocumentation.

The module implements both the normal and wide char variants of the console I/Oapi. The normal API deals only with ASCII characters and is of limited usefor internationalized applications. The wide char API should be used whereever possible.

在 3.3 版更改: Operations in this module now raise OSError where IOErrorwas raised.

File Operations

  • msvcrt.locking(fd, mode, nbytes)

  • Lock part of a file based on file descriptor fd from the C runtime. RaisesOSError on failure. The locked region of the file extends from thecurrent file position for nbytes bytes, and may continue beyond the end of thefile. mode must be one of the LK_* constants listed below. Multipleregions in a file may be locked at the same time, but may not overlap. Adjacentregions are not merged; they must be unlocked individually.

  • msvcrt.LK_LOCK

  • msvcrt.LK_RLCK

  • Locks the specified bytes. If the bytes cannot be locked, the programimmediately tries again after 1 second. If, after 10 attempts, the bytes cannotbe locked, OSError is raised.

  • msvcrt.LK_NBLCK

  • msvcrt.LK_NBRLCK

  • Locks the specified bytes. If the bytes cannot be locked, OSError israised.

  • msvcrt.LK_UNLCK

  • Unlocks the specified bytes, which must have been previously locked.

  • msvcrt.setmode(fd, flags)

  • Set the line-end translation mode for the file descriptor fd. To set it totext mode, flags should be os.O_TEXT; for binary, it should beos.O_BINARY.

  • msvcrt.openosfhandle(_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,and os.O_TEXT. The returned file descriptor may be used as a parameterto os.fdopen() to create a file object.

  • msvcrt.getosfhandle(_fd)

  • Return the file handle for the file descriptor fd. Raises OSError iffd is not recognized.

Console I/O

  • msvcrt.kbhit()

  • Return True if a keypress is waiting to be read.

  • 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 keypressis not already available, but will not wait for Enter to bepressed. If the pressed key was a special function key, this willreturn '\000' or '\xe0'; the next call will return the keycode.The Control-C keypress cannot be read with this function.

  • msvcrt.getwch()

  • Wide char variant of getch(), returning a Unicode value.

  • msvcrt.getche()

  • Similar to getch(), but the keypress will be echoed if it represents aprintable character.

  • msvcrt.getwche()

  • Wide char variant of getche(), returning a Unicode value.

  • msvcrt.putch(char)

  • Print the byte string char to the console without buffering.

  • msvcrt.putwch(unicode_char)

  • Wide char variant of putch(), accepting a Unicode value.

  • msvcrt.ungetch(char)

  • Cause the byte string char to be "pushed back" into the console buffer;it will be the next character read by getch() or getche().

  • msvcrt.ungetwch(unicode_char)

  • Wide char variant of ungetch(), accepting a Unicode value.

Other Functions

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