From 84e26b6d5d563781e1b78ddd3b1b95d5a4137617 Mon Sep 17 00:00:00 2001 From: Raymond Hettinger Date: Wed, 31 Oct 2007 21:57:58 +0000 Subject: Clarify the reasons why pickle is almost always better than marshal --- Doc/library/marshal.rst | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/Doc/library/marshal.rst b/Doc/library/marshal.rst index 6927067..8efcbb7 100644 --- a/Doc/library/marshal.rst +++ b/Doc/library/marshal.rst @@ -25,7 +25,9 @@ transfer of Python objects through RPC calls, see the modules :mod:`pickle` and writing the "pseudo-compiled" code for 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 :mod:`pickle` module instead. +de-serializing Python objects, use the :mod:`pickle` module instead -- the +performance is comparable, version independence is guaranteed, and pickle +supports a substantially wider range of objects than marshal. .. warning:: @@ -43,6 +45,12 @@ themselves supported; and recursive lists and dictionaries should not be written (they will cause infinite loops). .. 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. + +.. warning:: On machines where C's ``long int`` type has more than 32 bits (such as the DEC Alpha), it is possible to create plain Python integers that are longer -- cgit v0.12