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109 lines
3.9 KiB
TeX
109 lines
3.9 KiB
TeX
\section{\module{msvcrt} --
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Useful routines from the MS VC++ runtime}
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\declaremodule{builtin}{msvcrt}
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\platform{Windows}
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\modulesynopsis{Miscellaneous useful routines from the MS VC++ runtime.}
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\sectionauthor{Fred L. Drake, Jr.}{fdrake@acm.org}
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These functions provide access to some useful capabilities on Windows
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platforms. Some higher-level modules use these functions to build the
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Windows implementations of their services. For example, the
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\refmodule{getpass} module uses this in the implementation of the
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\function{getpass()} function.
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Further documentation on these functions can be found in the Platform
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API documentation.
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\subsection{File Operations \label{msvcrt-files}}
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\begin{funcdesc}{locking}{fd, mode, nbytes}
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Lock part of a file based on file descriptor \var{fd} from the C
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runtime. Raises \exception{IOError} on failure. The locked region
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of the file extends from the current file position for \var{nbytes}
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bytes, and may continue beyond the end of the file. \var{mode} must
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be one of the \constant{LK_\var{*}} constants listed below.
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Multiple regions in a file may be locked at the same time, but may
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not overlap. Adjacent regions are not merged; they must be unlocked
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individually.
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\end{funcdesc}
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\begin{datadesc}{LK_LOCK}
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\dataline{LK_RLCK}
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Locks the specified bytes. If the bytes cannot be locked, the
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program immediately tries again after 1 second. If, after 10
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attempts, the bytes cannot be locked, \exception{IOError} is
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raised.
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\end{datadesc}
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\begin{datadesc}{LK_NBLCK}
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\dataline{LK_NBRLCK}
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Locks the specified bytes. If the bytes cannot be locked,
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\exception{IOError} is raised.
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\end{datadesc}
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\begin{datadesc}{LK_UNLCK}
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Unlocks the specified bytes, which must have been previously locked.
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\end{datadesc}
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\begin{funcdesc}{setmode}{fd, flags}
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Set the line-end translation mode for the file descriptor \var{fd}.
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To set it to text mode, \var{flags} should be \constant{os.O_TEXT};
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for binary, it should be \constant{os.O_BINARY}.
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\end{funcdesc}
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\begin{funcdesc}{open_osfhandle}{handle, flags}
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Create a C runtime file descriptor from the file handle
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\var{handle}. The \var{flags} parameter should be a bit-wise OR of
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\constant{os.O_APPEND}, \constant{os.O_RDONLY}, and
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\constant{os.O_TEXT}. The returned file descriptor may be used as a
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parameter to \function{os.fdopen()} to create a file object.
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\end{funcdesc}
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\begin{funcdesc}{get_osfhandle}{fd}
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Return the file handle for the file descriptor \var{fd}. Raises
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\exception{IOError} if \var{fd} is not recognized.
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\end{funcdesc}
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\subsection{Console I/O \label{msvcrt-console}}
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\begin{funcdesc}{kbhit}{}
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Return true if a keypress is waiting to be read.
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\end{funcdesc}
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\begin{funcdesc}{getch}{}
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Read a keypress and return the resulting character. Nothing is
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echoed to the console. This call will block if a keypress is not
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already available, but will not wait for \kbd{Enter} to be pressed.
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If the pressed key was a special function key, this will return
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\code{'\e000'} or \code{'\e xe0'}; the next call will return the
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keycode. The \kbd{Control-C} keypress cannot be read with this
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function.
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\end{funcdesc}
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\begin{funcdesc}{getche}{}
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Similar to \function{getch()}, but the keypress will be echoed if it
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represents a printable character.
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\end{funcdesc}
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\begin{funcdesc}{putch}{char}
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Print the character \var{char} to the console without buffering.
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\end{funcdesc}
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\begin{funcdesc}{ungetch}{char}
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Cause the character \var{char} to be ``pushed back'' into the
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console buffer; it will be the next character read by
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\function{getch()} or \function{getche()}.
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\end{funcdesc}
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\subsection{Other Functions \label{msvcrt-other}}
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\begin{funcdesc}{heapmin}{}
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Force the \cfunction{malloc()} heap to clean itself up and return
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unused blocks to the operating system. This only works on Windows
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NT. On failure, this raises \exception{IOError}.
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\end{funcdesc}
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