[zeromq-dev] default MAX_SOCKETS on Windows set to 63?

[Charles Remes]

I received a bug report from a user who compiled zeromq 4.0.3 on Windows using 32-bit mingw. The code that blew up was:

context = LibZMQ.zmq_ctx_new
rc = LibZMQ.zmq_ctx_set(context, ZMQ::MAX_SOCKETS, 1023)

At this point, “rc” was returning -1 and the error message is “Invalid Argument”. After playing around with this a bit I discovered that the default MAX_SOCKETS was 63 on this platform.

context = LibZMQ.zmq_ctx_new
print LibZMQ.zmq_ctx_set(context, ZMQ::MAX_SOCKETS) # => prints “63”

So, trying to set a value above 63 always fails. 

For further confirmation, I ran “make check” and noted that “test_ctx_options” also fails (though it doesn’t tell me why).

Does anyone know why MAX_SOCKETS is set to 63 when compiling on Windows using mingw? When I look at the source, MAX_SOCKETS_DFLT is set to 1023!

cr