[zeromq-dev] Java API is not notifed of C++ assert failures.

Pieter Hintjens ph at imatix.com
Wed Apr 15 18:20:50 CEST 2009

On Wed, Apr 15, 2009 at 5:56 PM, Martin Sustrik <sustrik at fastmq.com> wrote:

> Second, 0MQ uses 'select' function to poll on the sockets. By default
> select handles at most 64 sockets on Win32. The limit can be increased
> by defining FD_SETSIZE macro to desired value before including winsocks
> (select_thread.hpp/cpp). Maybe we should increase it to some reasonable
> value ourselves (256?)

FD_SETSIZE is not the maximum number of open sockets, it's the highest
socket handle number.  Win32 allocates socket numbers with holes, so
the default value of 64 will give you maybe 16 sockets (a guess, not
tested).  Try printing the actual socket numbers.

Increasing FD_SETSIZE to something reasonable (1024 or higher) is
pretty much mandatory for any win32 server.  The APR package we use in
OpenAMQ sets it to 1024.  I've heard of people raising it to 16K on
win32 without trouble.


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