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Diffstat (limited to 'Doc/lib/libshelve.tex')
| -rw-r--r-- | Doc/lib/libshelve.tex | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/Doc/lib/libshelve.tex b/Doc/lib/libshelve.tex index 0dec230..a232add 100644 --- a/Doc/lib/libshelve.tex +++ b/Doc/lib/libshelve.tex @@ -1,7 +1,8 @@ -\section{Built-in module \sectcode{shelve}} +\section{Standard Module \sectcode{shelve}} \stmodindex{shelve} \stmodindex{pickle} \bimodindex{dbm} +\bimodindex{gdbm} A ``shelf'' is a persistent, dictionary-like object. The difference with ``dbm'' databases is that the values (not the keys!) in a shelf @@ -48,8 +49,11 @@ Dependent on the implementation, closing a persistent dictionary may or may not be necessary to flush changes to disk. \item -The \code{shelve} module does not support {\em concurrent} access to -shelved objects. Two programs should not try to simultaneously access -the same shelf. +The \code{shelve} module does not support {\em concurrent} read/write +access to shelved objects. (Multiple simultaneous read accesses are +safe.) When a program has a shelf open for writing, no other program +should have it open for reading or writing. \UNIX{} file locking can +be used to solve this, but this differs across \UNIX{} versions and +requires knowledge about the database implementation used. \end{itemize} |