Author: raymond.hettinger Date: Wed Oct 31 23:02:21 2007 New Revision: 58738 Modified: python/branches/release25-maint/Doc/lib/libmarshal.tex Log: Clarify the reasons why pickle is almost always better than marshal Modified: python/branches/release25-maint/Doc/lib/libmarshal.tex ============================================================================== --- python/branches/release25-maint/Doc/lib/libmarshal.tex (original) +++ python/branches/release25-maint/Doc/lib/libmarshal.tex Wed Oct 31 23:02:21 2007 @@ -26,7 +26,9 @@ Python modules of \file{.pyc} files. Therefore, the Python maintainers reserve the right to modify the marshal format in backward incompatible ways should the need arise. If you're serializing and -de-serializing Python objects, use the \module{pickle} module instead. +de-serializing Python objects, use the \module{pickle} module instead + --- the performance is comparable, version independence is guaranteed, +and pickle supports a substantially wider range of objects than marshal. \refstmodindex{pickle} \refstmodindex{shelve} \obindex{code} @@ -47,6 +49,12 @@ therein are themselves supported; and recursive lists and dictionaries should not be written (they will cause infinite loops). +\begin{notice}[warning] +Some unsupported types such as subclasses of builtins will appear to marshal +and unmarshal correctly, but in fact, their type will change and the +additional subclass functionality and instance attributes will be lost. +\end{notice} + \strong{Caveat:} On machines where C's \code{long int} type has more than 32 bits (such as the DEC Alpha), it is possible to create plain Python integers that are longer than 32 bits.