[Python-Dev] The curious case of 255 function arguments
storchaka at gmail.com
Mon Aug 6 05:17:52 EDT 2018
06.08.18 08:13, Stephen McDowell пише:
> I've looked at the C code for a while and it is entirely non-obvious
> what would lead to python *2* /allowing/ >255 arguments. Anybody happen
> to know how / why the python *2* versions *succeed*?
The error message is misleading. It should be "more than 255
parameters". This limitation is due to the optimization used in Python 3
for call variables (see https://bugs.python.org/issue12399 for details).
In all versions <3.7 there is a limitation on the number of explicit
function arguments because of the limitation of the CALL_FUNCTION opcode.
> Thank you for reading, this is not a problem, just a burning desire for
> closure (even if anecdotal) as to how this can be. I deeply love
> python, and am not complaining! I stumbled across this and found it
> truly confounding, and thought the gurus here may happen to recall what
> changed in 3.x that lead the the error condition actually being asserted :)
Read the history of the code. Commit messages usually contain
explanations or references to issues.
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