PEP 3147 - new .pyc format

Martin v. Loewis martin at
Sun Jan 31 11:17:19 CET 2010

> True. You might also want to note that "Python 2.6 -U" appears to have a
> different magic number from "Python 2.6" and "Python 2.6 -O".
> I don't know whether they always change for each new version.

Here is a recent list of magic numbers:

       Python 2.6a0: 62151 (peephole optimizations and STORE_MAP opcode)
       Python 2.6a1: 62161 (WITH_CLEANUP optimization)
       Python 2.7a0: 62171 (optimize list comprehensions/change LIST_APPEND)
       Python 2.7a0: 62181 (optimize conditional branches:
			    introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE)
       Python 2.7a0  62191 (introduce SETUP_WITH)
       Python 2.7a0  62201 (introduce BUILD_SET)
       Python 2.7a0  62211 (introduce MAP_ADD and SET_ADD)

#define MAGIC (62211 | ((long)'\r'<<16) | ((long)'\n'<<24))


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