\section{Standard Modules \sectcode{anydbm} and \sectcode{dumbdbm}}
\label{module-anydbm}
\label{module-dumbdbm}
\stmodindex{anydbm}
\stmodindex{dumbdbm}

\module{anydbm} is a generic interface to variants of the DBM
database--DBM, GDBM, or dbhash.  If none of these modules is
installed, the slow-but-simple implementation in module \module{dumbdbm}
will be used.   Both modules provide the same interface:

% not the best solution, but it's what you get for documenting both
% at the same time.
\setindexsubitem{(in modules anydbm, dumbdbm)}

\begin{funcdesc}{open}{filename\optional{\, flag\, mode}}
Open the database file \var{filename} and return a corresponding object.
The optional \var{flag} argument can be
\code{'r'} to open an existing database for reading only,
\code{'w'} to open an existing database for reading and writing,
\code{'c'} to create the database if it doesn't exist, or
\code{'n'}, which will always create a new empty database.  If not
specified, the default value is \code{'r'}.

The optional \var{mode} argument is the \UNIX{} mode of the file, used
only when the database has to be created.  It defaults to octal
\code{0666} (and will be modified by the prevailing umask).
\end{funcdesc}

The object returned by \function{open()} supports most of the same
functionality as dictionaries; keys and their corresponding values can
be stored, retrieved, and deleted, and the \method{has_key()} and
\method{keys()} methods are available.  Keys and values must always be
strings.

Both modules also export the exception \exception{error}, which is
raised for various problems.  The \exception{anydbm.error} exception
is simply a different name for the \exception{error} exception of the
underlying implementation module used.