[cfarm-users] Max UDP dgram size on M1 machine (gcc304)

Bruno Haible bruno at clisp.org
Wed Mar 24 21:45:40 CET 2021

Hi Kaz,

> On Mac OS, there are, by default, bizarre restrictions on IP datagram 
> sizes
> in the protocol stack.
> ...
> I have a test case involving UDP that works on numerous platforms, the
> oddball being MacOS

So, the test machine was useful to you: it has told you that a test case
(and presumably also some functionality of your package) is not working
on stock macOS.

> Would it be possible to put this configuration into effect:
>     sysctl -w net.inet.udp.maxdgram=65535
> or something similar

This would have the effect that for other packages than yours, the
developer tests it on the compilefarm machine, finds that everything
is all right, then releases their package — and then their users
will send in bug reports saying "this does not work on my machine,
a stock macOS".

In other words, it would reduce the usefulness of the compilefarm

You can easily disable the particular test in your package on macOS.
In gnulib, for example, we have to disable 89 tests on FreeBSD,
33 tests on NetBSD, 4 tests on OpenBSD, 67 tests on Solaris, and
39 tests on macOS. Platforms are not all the same.


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