[zeromq-dev] UDP Multicast - Problem with large message sizes?

Stephan Opfer opfer at vs.uni-kassel.de
Mon Sep 9 21:09:31 CEST 2019

Hi all,

when I try to send large messages (~65kB) via UDP Multicast (per draft 
API, RADIO/DISH), I instantly get

Bad file descriptor (src/epoll.cpp:113)
#0  0x7faad868ee90 in /usr/lib/x86_64-linux-gnu/libzmq.so.5 (?+0x0)
#1  0x7faad868e870 in /usr/lib/x86_64-linux-gnu/libzmq.so.5 (?+0x0)
#2  0x7faad86d72f0 in /usr/lib/x86_64-linux-gnu/libzmq.so.5 (?+0x0)
#3  0x7faad86d8740 in /usr/lib/x86_64-linux-gnu/libzmq.so.5 (?+0x0)
#4  0x7faad86d73d0 in /usr/lib/x86_64-linux-gnu/libzmq.so.5 (?+0x0)
#5  0x7faad8692370 in /usr/lib/x86_64-linux-gnu/libzmq.so.5 (?+0x0)
#6  0x7faad868e120 in /usr/lib/x86_64-linux-gnu/libzmq.so.5 (?+0x0)
#7  0x7faad86d3440 in /usr/lib/x86_64-linux-gnu/libzmq.so.5 (?+0x0)
#8  0x7faad75b46db in /lib/x86_64-linux-gnu/libpthread.so.0 
#9  0x7faad699e8c8 in /lib/x86_64-linux-gnu/libc.so.6 (clone+0x3f)

Is it known, that the draft API has Problems with large message sizes?

What does the assertion in line epoll.cpp:113 actually check and what 
could be the reason to make it fail?

Do you need a MWE in order to investigate it? I probably can create a 
simple main, that reproduces this error.

Last remark (not 100% sure about this): If I reduce the message size to 
~2kB, it takes several of these message (~254) to get this error, but 
the number of messages seems to be always the same.



Distributed Systems Research Group
Stephan Opfer  T. +49 561 804-6283  F. +49 561 804-6277
Univ. Kassel,  FB 16,  Wilhelmshöher Allee 73,  D-34121 Kassel
WWW: http://www.uni-kassel.de/go/vs_stephan-opfer/

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