415 lines
14 KiB
TeX
415 lines
14 KiB
TeX
\section{\module{_winreg} --
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Windows registry access}
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\declaremodule[-winreg]{extension}{_winreg}
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\platform{Windows}
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\modulesynopsis{Routines and objects for manipulating the Windows registry.}
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\sectionauthor{Mark Hammond}{MarkH@ActiveState.com}
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\versionadded{2.0}
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These functions expose the Windows registry API to Python. Instead of
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using an integer as the registry handle, a handle object is used to
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ensure that the handles are closed correctly, even if the programmer
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neglects to explicitly close them.
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This module exposes a very low-level interface to the Windows
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registry; it is expected that in the future a new \code{winreg}
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module will be created offering a higher-level interface to the
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registry API.
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This module offers the following functions:
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\begin{funcdesc}{CloseKey}{hkey}
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Closes a previously opened registry key.
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The hkey argument specifies a previously opened key.
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Note that if \var{hkey} is not closed using this method (or via
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\method{handle.Close()}), it is closed when the \var{hkey} object
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is destroyed by Python.
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\end{funcdesc}
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\begin{funcdesc}{ConnectRegistry}{computer_name, key}
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Establishes a connection to a predefined registry handle on
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another computer, and returns a \dfn{handle object}
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\var{computer_name} is the name of the remote computer, of the
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form \code{r"\e\e computername"}. If \code{None}, the local computer
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is used.
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\var{key} is the predefined handle to connect to.
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The return value is the handle of the opened key.
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If the function fails, an \exception{EnvironmentError} exception is
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raised.
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\end{funcdesc}
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\begin{funcdesc}{CreateKey}{key, sub_key}
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Creates or opens the specified key, returning a \dfn{handle object}
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\var{key} is an already open key, or one of the predefined
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\constant{HKEY_*} constants.
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\var{sub_key} is a string that names the key this method opens
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or creates.
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If \var{key} is one of the predefined keys, \var{sub_key} may
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be \code{None}. In that case, the handle returned is the same key handle
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passed in to the function.
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If the key already exists, this function opens the existing key.
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The return value is the handle of the opened key.
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If the function fails, an \exception{EnvironmentError} exception is
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raised.
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\end{funcdesc}
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\begin{funcdesc}{DeleteKey}{key, sub_key}
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Deletes the specified key.
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\var{key} is an already open key, or any one of the predefined
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\constant{HKEY_*} constants.
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\var{sub_key} is a string that must be a subkey of the key
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identified by the \var{key} parameter. This value must not be
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\code{None}, and the key may not have subkeys.
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\emph{This method can not delete keys with subkeys.}
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If the method succeeds, the entire key, including all of its values,
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is removed. If the method fails, an \exception{EnvironmentError}
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exception is raised.
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\end{funcdesc}
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\begin{funcdesc}{DeleteValue}{key, value}
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Removes a named value from a registry key.
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\var{key} is an already open key, or one of the predefined
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\constant{HKEY_*} constants.
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\var{value} is a string that identifies the value to remove.
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\end{funcdesc}
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\begin{funcdesc}{EnumKey}{key, index}
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Enumerates subkeys of an open registry key, returning a string.
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\var{key} is an already open key, or any one of the predefined
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\constant{HKEY_*} constants.
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\var{index} is an integer that identifies the index of the key to
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retrieve.
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The function retrieves the name of one subkey each time it
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is called. It is typically called repeatedly until an
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\exception{EnvironmentError} exception
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is raised, indicating, no more values are available.
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\end{funcdesc}
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\begin{funcdesc}{EnumValue}{key, index}
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Enumerates values of an open registry key, returning a tuple.
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\var{key} is an already open key, or any one of the predefined
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\constant{HKEY_*} constants.
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\var{index} is an integer that identifies the index of the value
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to retrieve.
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The function retrieves the name of one subkey each time it is
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called. It is typically called repeatedly, until an
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\exception{EnvironmentError} exception is raised, indicating
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no more values.
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The result is a tuple of 3 items:
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\begin{tableii}{c|p{3in}}{code}{Index}{Meaning}
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\lineii{0}{A string that identifies the value name}
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\lineii{1}{An object that holds the value data, and whose
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type depends on the underlying registry type}
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\lineii{2}{An integer that identifies the type of the value data}
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\end{tableii}
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\end{funcdesc}
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\begin{funcdesc}{FlushKey}{key}
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Writes all the attributes of a key to the registry.
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\var{key} is an already open key, or one of the predefined
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\constant{HKEY_*} constants.
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It is not necessary to call RegFlushKey to change a key.
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Registry changes are flushed to disk by the registry using its lazy
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flusher. Registry changes are also flushed to disk at system
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shutdown. Unlike \function{CloseKey()}, the \function{FlushKey()} method
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returns only when all the data has been written to the registry.
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An application should only call \function{FlushKey()} if it requires absolute
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certainty that registry changes are on disk.
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\emph{If you don't know whether a \function{FlushKey()} call is required, it
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probably isn't.}
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\end{funcdesc}
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\begin{funcdesc}{RegLoadKey}{key, sub_key, file_name}
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Creates a subkey under the specified key and stores registration
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information from a specified file into that subkey.
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\var{key} is an already open key, or any of the predefined
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\constant{HKEY_*} constants.
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\var{sub_key} is a string that identifies the sub_key to load.
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\var {file_name} is the name of the file to load registry data from.
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This file must have been created with the \function{SaveKey()} function.
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Under the file allocation table (FAT) file system, the filename may not
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have an extension.
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A call to LoadKey() fails if the calling process does not have the
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\constant{SE_RESTORE_PRIVILEGE} privilege. Note that privileges
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are different than permissions - see the Win32 documentation for
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more details.
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If \var{key} is a handle returned by \function{ConnectRegistry()},
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then the path specified in \var{fileName} is relative to the
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remote computer.
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The Win32 documentation implies \var{key} must be in the
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\constant{HKEY_USER} or \constant{HKEY_LOCAL_MACHINE} tree.
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This may or may not be true.
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\end{funcdesc}
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\begin{funcdesc}{OpenKey}{key, sub_key\optional{, res\code{ = 0}}\optional{, sam\code{ = \constant{KEY_READ}}}}
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Opens the specified key, returning a \dfn{handle object}
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\var{key} is an already open key, or any one of the predefined
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\constant{HKEY_*} constants.
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\var{sub_key} is a string that identifies the sub_key to open.
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\var{res} is a reserved integer, and must be zero. The default is zero.
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\var{sam} is an integer that specifies an access mask that describes
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the desired security access for the key. Default is \constant{KEY_READ}
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The result is a new handle to the specified key.
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If the function fails, \exception{EnvironmentError} is raised.
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\end{funcdesc}
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\begin{funcdesc}{OpenKeyEx}{}
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The functionality of \function{OpenKeyEx()} is provided via
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\function{OpenKey()}, by the use of default arguments.
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\end{funcdesc}
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\begin{funcdesc}{QueryInfoKey}{key}
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Returns information about a key, as a tuple.
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\var{key} is an already open key, or one of the predefined
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\constant{HKEY_*} constants.
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The result is a tuple of 3 items:
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\begin{tableii}{c|p{3in}}{code}{Index}{Meaning}
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\lineii{0}{An integer giving the number of sub keys this key has.}
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\lineii{1}{An integer giving the number of values this key has.}
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\lineii{2}{A long integer giving when the key was last modified (if
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available) as 100's of nanoseconds since Jan 1, 1600.}
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\end{tableii}
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\end{funcdesc}
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\begin{funcdesc}{QueryValue}{key, sub_key}
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Retrieves the unnamed value for a key, as a string
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\var{key} is an already open key, or one of the predefined
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\constant{HKEY_*} constants.
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\var{sub_key} is a string that holds the name of the subkey with which
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the value is associated. If this parameter is \code{None} or empty, the
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function retrieves the value set by the \function{SetValue()} method
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for the key identified by \var{key}.
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Values in the registry have name, type, and data components. This
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method retrieves the data for a key's first value that has a NULL name.
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But the underlying API call doesn't return the type, Lame Lame Lame,
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DO NOT USE THIS!!!
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\end{funcdesc}
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\begin{funcdesc}{QueryValueEx}{key, value_name}
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Retrieves the type and data for a specified value name associated with
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an open registry key.
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\var{key} is an already open key, or one of the predefined
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\constant{HKEY_*} constants.
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\var{value_name} is a string indicating the value to query.
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The result is a tuple of 2 items:
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\begin{tableii}{c|p{3in}}{code}{Index}{Meaning}
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\lineii{0}{The value of the registry item.}
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\lineii{1}{An integer giving the registry type for this value.}
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\end{tableii}
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\end{funcdesc}
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\begin{funcdesc}{SaveKey}{key, file_name}
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Saves the specified key, and all its subkeys to the specified file.
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\var{key} is an already open key, or one of the predefined
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\constant{HKEY_*} constants.
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\var{file_name} is the name of the file to save registry data to.
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This file cannot already exist. If this filename includes an extension,
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it cannot be used on file allocation table (FAT) file systems by the
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\method{LoadKey()}, \method{ReplaceKey()} or
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\method{RestoreKey()} methods.
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If \var{key} represents a key on a remote computer, the path
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described by \var{file_name} is relative to the remote computer.
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The caller of this method must possess the \constant{SeBackupPrivilege}
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security privilege. Note that privileges are different than permissions
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- see the Win32 documentation for more details.
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This function passes NULL for \var{security_attributes} to the API.
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\end{funcdesc}
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\begin{funcdesc}{SetValue}{key, sub_key, type, value}
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Associates a value with a specified key.
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\var{key} is an already open key, or one of the predefined
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\constant{HKEY_*} constants.
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\var{sub_key} is a string that names the subkey with which the value
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is associated.
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\var{type} is an integer that specifies the type of the data.
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Currently this must be \constant{REG_SZ}, meaning only strings are
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supported. Use the \function{SetValueEx()} function for support for
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other data types.
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\var{value} is a string that specifies the new value.
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If the key specified by the \var{sub_key} parameter does not exist,
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the SetValue function creates it.
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Value lengths are limited by available memory. Long values (more than
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2048 bytes) should be stored as files with the filenames stored in
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the configuration registry. This helps the registry perform
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efficiently.
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The key identified by the \var{key} parameter must have been
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opened with \constant{KEY_SET_VALUE} access.
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\end{funcdesc}
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\begin{funcdesc}{SetValueEx}{key, value_name, reserved, type, value}
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Stores data in the value field of an open registry key.
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\var{key} is an already open key, or one of the predefined
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\constant{HKEY_*} constants.
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\var{sub_key} is a string that names the subkey with which the
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value is associated.
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\var{type} is an integer that specifies the type of the data.
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This should be one of the following constants defined in this module:
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\begin{tableii}{l|p{3in}}{constant}{Constant}{Meaning}
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\lineii{REG_BINARY}{Binary data in any form.}
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\lineii{REG_DWORD}{A 32-bit number.}
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\lineii{REG_DWORD_LITTLE_ENDIAN}{A 32-bit number in little-endian format.}
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\lineii{REG_DWORD_BIG_ENDIAN}{A 32-bit number in big-endian format.}
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\lineii{REG_EXPAND_SZ}{Null-terminated string containing references
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to environment variables (\samp{\%PATH\%}).}
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\lineii{REG_LINK}{A Unicode symbolic link.}
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\lineii{REG_MULTI_SZ}{A sequence of null-terminated strings,
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terminated by two null characters. (Python handles
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this termination automatically.)}
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\lineii{REG_NONE}{No defined value type.}
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\lineii{REG_RESOURCE_LIST}{A device-driver resource list.}
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\lineii{REG_SZ}{A null-terminated string.}
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\end{tableii}
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\var{reserved} can be anything - zero is always passed to the
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API.
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\var{value} is a string that specifies the new value.
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This method can also set additional value and type information for the
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specified key. The key identified by the key parameter must have been
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opened with \constant{KEY_SET_VALUE} access.
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To open the key, use the \function{CreateKeyEx()} or
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\function{OpenKey()} methods.
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Value lengths are limited by available memory. Long values (more than
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2048 bytes) should be stored as files with the filenames stored in
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the configuration registry. This helps the registry perform efficiently.
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\end{funcdesc}
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\subsection{Registry Handle Objects \label{handle-object}}
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This object wraps a Windows HKEY object, automatically closing it when
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the object is destroyed. To guarantee cleanup, you can call either
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the \method{Close()} method on the object, or the
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\function{CloseKey()} function.
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All registry functions in this module return one of these objects.
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All registry functions in this module which accept a handle object
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also accept an integer, however, use of the handle object is
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encouraged.
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Handle objects provide semantics for \method{__nonzero__()} - thus
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\begin{verbatim}
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if handle:
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print "Yes"
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\end{verbatim}
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will print \code{Yes} if the handle is currently valid (has not been
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closed or detached).
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The object also support comparison semantics, so handle
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objects will compare true if they both reference the same
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underlying Windows handle value.
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Handle objects can be converted to an integer (e.g., using the
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builtin \function{int()} function), in which case the underlying
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Windows handle value is returned. You can also use the
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\method{Detach()} method to return the integer handle, and
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also disconnect the Windows handle from the handle object.
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\begin{methoddesc}{Close}{}
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Closes the underlying Windows handle.
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If the handle is already closed, no error is raised.
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\end{methoddesc}
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\begin{methoddesc}{Detach}{}
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Detaches the Windows handle from the handle object.
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The result is an integer (or long on 64 bit Windows) that holds
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the value of the handle before it is detached. If the
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handle is already detached or closed, this will return zero.
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After calling this function, the handle is effectively invalidated,
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but the handle is not closed. You would call this function when
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you need the underlying Win32 handle to exist beyond the lifetime
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of the handle object.
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\end{methoddesc}
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