Doc/libdbm.tex

   1 \section{Built-in Module \sectcode{dbm}}
   2 \bimodindex{dbm}
   3
   4 The \code{dbm} module provides an interface to the {\UNIX}
   5 \code{(n)dbm} library.  Dbm objects behave like mappings
   6 (dictionaries), except that keys and values are always strings.
   7 Printing a dbm object doesn't print the keys and values, and the
   8 \code{items()} and \code{values()} methods are not supported.
   9
  10 See also the \code{gdbm} module, which provides a similar interface
  11 using the GNU GDBM library.
  12 \bimodindex{gdbm}
  13
  14 The module defines the following constant and functions:
  15
  16 \renewcommand{\indexsubitem}{(in module dbm)}
  17 \begin{excdesc}{error}
  18 Raised on dbm-specific errors, such as I/O errors. \code{KeyError} is
  19 raised for general mapping errors like specifying an incorrect key.
  20 \end{excdesc}
  21
  22 \begin{funcdesc}{open}{filename\, \optional{flag\, \optional{mode}}}
  23 Open a dbm database and return a dbm object.  The \var{filename}
  24 argument is the name of the database file (without the \file{.dir} or
  25 \file{.pag} extensions).
  26
  27 The optional \var{flag} argument can be
  28 \code{'r'} (to open an existing database for reading only --- default),
  29 \code{'w'} (to open an existing database for reading and writing),
  30 \code{'c'} (which creates the database if it doesn't exist), or
  31 \code{'n'} (which always creates a new empty database).
  32
  33 The optional \var{mode} argument is the \UNIX{} mode of the file, used
  34 only when the database has to be created.  It defaults to octal
  35 \code{0666}.
  36 \end{funcdesc}