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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 Windows
implementations of their services. For example, the getpass module uses
this in the implementation of the getpass() function.
Further documentation on these functions can be found in the Platform API documentation.
The module implements both the normal and wide char variants of the console I/O api. The normal API deals only with ASCII characters and is of limited use for internationalized applications. The wide char API should be used where ever possible.
Availability: Windows.
File Operations
- msvcrt.locking(fd, mode, nbytes)
Lock part of a file based on file descriptor fd from the C runtime. Raises
OSErroron 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 theLK_*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.Raises an auditing event
msvcrt.lockingwith argumentsfd,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,
OSErroris raised.
- msvcrt.LK_NBLCK
- msvcrt.LK_NBRLCK
Locks the specified bytes. If the bytes cannot be locked,
OSErroris raised.
- msvcrt.setmode(fd, flags)
Set the line-end translation mode for the file descriptor fd. To set it to text mode, flags should be
os.O_TEXT; for binary, it should beos.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_TEXTandos.O_NOINHERIT. The returned file descriptor may be used as a parameter toos.fdopen()to create a file object.The file descriptor is inheritable by default. Pass
os.O_NOINHERITflag to make it non inheritable.Raises an auditing event
msvcrt.open_osfhandlewith argumentshandle,flags.
- msvcrt.get_osfhandle(fd)
Return the file handle for the file descriptor fd. Raises
OSErrorif fd is not recognized.Raises an auditing event
msvcrt.get_osfhandlewith argumentfd.
Console I/O
- 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()
Wide char variant of
getch(), returning a Unicode value.
- msvcrt.getche()
Similar to
getch(), but the keypress will be echoed if it represents a printable character.
- msvcrt.getwche()
Wide char variant of
getche(), returning a Unicode value.
- 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()orgetche().
- 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 to the operating system. On failure, this raisesOSError.
- 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 orREPORT_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 apps 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 theCRT_*constants listed below. mode must be one of theCRTDBG_*constants listed below. Only available in debug build of Python.
- msvcrt.CrtSetReportFile(type, file)
After you use
CrtSetReportMode()to specifyCRTDBG_MODE_FILE, you can specify the file handle to receive the message text. type must be one of theCRT_*constants listed below. file should be the file handle your want specified. Only available in debug build of Python.
- 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, andIgnorebuttons.