I am following the pub-sub example listed, modified slightly because I didn't need the publisher (running the unedited example gives me the same error), and I can't get past the creation of a subscriber without crashing. the code looks like the following:

public var endpoint = "tcp://127.0.0.1:5550"

public func subscribe(topic: String, callback: @escaping (_ name: String,_ recieved: String) -> Void) {
    do {
        let context = try SwiftyZeroMQ.Context()
        let subscriber = try context.socket(.subscribe)
        
        let subscribers = [
            subscriber: "Subscriber #1"
        ]
        
        try subscriber.setSubscribe(topic)

        // Brief wait to let everything hook up
        usleep(250)
        
        let poller = SwiftyZeroMQ.Poller()
        try poller.register(socket: subscriber, flags: .pollIn)
        
        func pollAndRecv() throws {
            let socks = try poller.poll(timeout: 1000)
            for subscriber in socks.keys {
                let name = subscribers[subscriber]
                if socks[subscriber] == SwiftyZeroMQ.PollFlags.pollIn {
                    let text = try subscriber.recv(options: .dontWait)
                    callback("\(name)", "\(text)")
                    print("\(name): received '\(text)'")
                } else {
                    print("\(name): Nothing")
                }
            }
            print("---")
        }
        
        try pollAndRecv();
        
    } catch {
        print(error)
    }
}

The stack looks like this:

I don't get any error messages in the console, execution simply stops on "dyld`dyld_fatal_error: -> 0x120009088 <+0>: brk #0x3"

and the last thing called in code was this

public init(context: Context, type : SocketType) throws {
    // Create socket
    let p : UnsafeMutableRawPointer? = zmq_socket(context.handle,
        type.rawValue)
    guard p != nil else {
        throw ZeroMQError.last
    }

    // Now we can assign socket handle safely
    handle = p!
    cleanupNeeded = true
}

with the debugger failing on this line: let p : UnsafeMutableRawPointer? = zmq_socket(context.handle, type.rawValue)

Any ideas or pointers would be much appreciated! Thanks for all the great work

I have a long running background process and I am running socket.recv() on a loop. The memory use is building up indefinitely and I get the attached memory leak report. From zeromq docs, they recommend calling zmq_msg_close after zmq_recv. Any ideas?

It looks like pub/sub doesn't work at the moment without first calling zmq_setsockopt on the subscriber. This is because the default for .subscribe sockets is to ignore all messages. We should start looking at wrapping zmq_setsockopt to get around this.

Providing a generic function as we have in the Context is not going to be so simple because, depending on the option name, different data types can be passed. I would suggest we either provide a method for each option name, or a method for each data type - the former seems neater but requires more boilerplate.

Hi @azawawi I just started using the latest from master so that I could try out a subscribe use case. It's great being able to pass through the extra socket options. I'm just wondering if it's too early, or should I expect it to work as it is? Happy to help out! James

Hello and thank you for this library !

I'm trying to implement zeroMQ with this lib but something seem to not work with iOS9 on my iPod touch.

do {
            // Define a TCP endpoint along with the text that we are going to send/recv
            let endpoint     = "tcp://<my_ip>"
            let textToBeSent = "{\"type\":\"connect\",\"apiToken\":\"<token>\"}"
            
            // Request socket
            let context      = try SwiftyZeroMQ.Context()
            let requestor    = try context.socket(.request) // THIS LINE CRASH
            try requestor.connect(endpoint)
            
            // Send it without waiting and check the reply on other socket
            try requestor.send(string: textToBeSent, options: .dontWait)
            let reply = try requestor.recv()
            print(reply)
        } catch {
            print(error)
        }

With this code, all work on iOS10 (with real device and simulator) and on iOS9 on simulator. But on my real device on iOS9 (iPod Touch 9.3.5) I have crash at this line : let requestor = try context.socket(.request) // THIS LINE CRASH

There is any issue with iOS9 ? I don't have any other real device for trying it ...

Thank you

Hiya! Just a couple methods I found useful—I need to work with multipart messages, which seems like it'd be a good addition to the Swifty library.

Let me know if this is useful to you too—no obligation to merge it! :)

Have a nice day, Tim

Hey, Thanks for merging the last stuff! As you pointed out there were a couple of issues with redundant tests / test failures as well as the fact that I hadn't added the pbxproj to the commit - this is all included in this pull request. Hope it looks okay. Jon

Added the ability to add curve security to a socket. Some tests were not passing - fixed. Added some new tests with different ZeroMQ patterns. Please shout if you think anything needs more work!

I'm having trouble sending messages. Using publish configuration and sending strings, sometimes they are sent, and sometimes nothing is send. Went they are not sent the memory usage of the app starts increasing until it is completely full and the app crashes.

Apparently this behaviour is random, can't really find out what makes it work sometimes but most of the time is not working. Any suggestion?

I've been trying out a new application on using an ipad as a wired zeromq messaging server, and I've been having some issues getting it to work properly when running on the actual hardware. It works completely fine in the simulator.

• iOS hardware: has both a pub and a sub. Both the pub and the sub are bound.
• Python client 1: has both a pub and a sub that connect to the iOS hardware.
• Python client 2: same situation, running exact the same code.
• Both clients share the same subscription.

If client 1 connects first, everything works fine. When client 2 connects, the iOS hardware never sends a message to client 2 after the initial behind the scenes connection messages. However, it sends the message to client 1 since they share the same subscription.

Using wireshark, I was able to confirm that client 2 never received the messages. Using it further, I was able to get the iOS hardware recognized as a network interface and run tcpdump to examine what's happening on the iOS hardware side of things.

The iOS hardware is never sending to client 2. Even if connection order happens in reverse and client 1 connects second, the exact same symptoms happen to client 1. It just won't send a message.

Looking at your code, it appears that sending a message is just wrapped into a data format and sent down to the attached zeromq binary. I'm wondering if how the binary is handling these sockets for the hardware architecture/software environment isn't correct to how pub/sub should work. It's either that, or iOS/hardware is limiting me from sending to the second client entirely.

In order to make sure I was setting up the architecture correctly, I set up the exact same situation using pyzmq. Pyzmq seems to work perfectly fine.

I was wondering if you had any insight into this.

I added a function to Socket.swift to remove a subscription filter (and I am curious why ZMQ_SUBSCRIBE is implemented but not ZMQ_UNSUBSCRIBE):

       public func unSubscribe(_ value: String?) throws {
           try self.setStringOption(ZMQ_UNSUBSCRIBE, value)
       }

I also modified setStringOption function because I was having memory issues:

Original setStringOption function

        /**
          Interface to set an option which takes a Swift String.
         */
        private func setStringOption(_ name: Int32, _ value: String?) throws {
            let optValLen = (value != nil)
                ? value!.characters.count
                : 0
            let optval = (value != nil)
                ? UnsafeRawPointer(value!)
                : UnsafeRawPointer([UInt8]())

            try self.setOption(name, optval, optValLen)
        }

Modified setStringOption function

        /**
          Interface to set an option which takes a Swift String.
         */
        private func setStringOption(_ name: Int32, _ value: String?) throws {            
            if let optval = value {
                let bufferPointer: UnsafePointer<UInt8> = optval.data(using: .utf8, allowLossyConversion: false)!.withUnsafeBytes({$0})
                try setOption(name, UnsafeRawPointer(bufferPointer), optval.characters.count)
            }else{
                try setOption(name, UnsafeRawPointer([UInt8]()), 0)
            }
        }

But, though rarely, I sometimes get the following crash:

#3. Crashed: xxxxx.queue

0  SwiftyZeroMQ                   0x1106b31c1 zmq::trie_t::rm(unsigned char*, unsigned long) + 333
1  SwiftyZeroMQ                   0x1106b3104 zmq::trie_t::rm(unsigned char*, unsigned long) + 144
2  SwiftyZeroMQ                   0x1106b3104 zmq::trie_t::rm(unsigned char*, unsigned long) + 144
3  SwiftyZeroMQ                   0x1106b3104 zmq::trie_t::rm(unsigned char*, unsigned long) + 144
4  SwiftyZeroMQ                   0x1106b3104 zmq::trie_t::rm(unsigned char*, unsigned long) + 144
5  SwiftyZeroMQ                   0x1106b3104 zmq::trie_t::rm(unsigned char*, unsigned long) + 144
6  SwiftyZeroMQ                   0x1106b3104 zmq::trie_t::rm(unsigned char*, unsigned long) + 144
7  SwiftyZeroMQ                   0x1106b3104 zmq::trie_t::rm(unsigned char*, unsigned long) + 144
8  SwiftyZeroMQ                   0x1106b3104 zmq::trie_t::rm(unsigned char*, unsigned long) + 144
9  SwiftyZeroMQ                   0x1106b3104 zmq::trie_t::rm(unsigned char*, unsigned long) + 144
10 SwiftyZeroMQ                   0x1106b3104 zmq::trie_t::rm(unsigned char*, unsigned long) + 144
11 SwiftyZeroMQ                   0x1106ba802 zmq::xsub_t::xsend(zmq::msg_t*) + 104
12 SwiftyZeroMQ                   0x1106add3b zmq::sub_t::xsetsockopt(int, void const*, unsigned long) + 163
13 SwiftyZeroMQ                   0x1106a1df2 zmq::socket_base_t::setsockopt(int, void const*, unsigned long) + 116
14 SwiftyZeroMQ                   0x110678436 _TFCV12SwiftyZeroMQ12SwiftyZeroMQ6SocketP33_3F544464429ADF695CBBDED00A72C2259setOptionfzTVs5Int32SVSi_T_ + 70
15 SwiftyZeroMQ                   0x110677db0 _TFCV12SwiftyZeroMQ12SwiftyZeroMQ6SocketP33_3F544464429ADF695CBBDED00A72C22515setStringOptionfzTVs5Int32GSqSS__T_ + 736
16 SwiftyZeroMQ                   0x110676ce0 _TFCV12SwiftyZeroMQ12SwiftyZeroMQ6Socket11unSubscribefzGSqSS_T_ + 160

Any ideas why it crashes on ZMQ_UNSUBSCRIBE?

https://pub.dev/packages/dartzmq/install Reference library, when I run I am runiinf into this wehn build xcframe from binary, I have no experience with xcode , can you please help to proceed further,

When unregistering from poller the socketMap dict is not updated. When registering again the poller somtimes get out of index. Suggested solution, clear dict entry in poller:

        public func unregister(socket: Socket) throws {
            let socketIndex = socketMap[socket]!
            sockets.remove(at: socketIndex)
            socketMap[socket] = nil

            // Update indices of all other sockets in the socket map
            for (socket, _) in sockets.suffix(from: socketIndex) {
                let socketIndex = socketMap[socket]!
                socketMap[socket] = socketIndex - 1
            }
        }

Edit: formatting

The issue is further described at stack overflow, here: [https://stackoverflow.com/questions/66063569/swiftyzeromq-publisher-does-not-recognise-subscriber-after-first-message-is-publ]

If anyone could prove me wrong or point me in a direction to a solution I'd be very grateful!

EDIT: New subscribers are picked up every time i rebind the publisher socket: pubSocket.bind(endPoint). (-> Throwing an error that the address is already in use, but there seems to be no harm). I also figured that it all works as intended when I run the code on the xcode iPhone simulator. Wonder if could be the different architectures or somehow connected to Apples Multicast Networking Entitlement.

Hi, I'm trying to build a command line tool on mac using this library, but since command line tools do not have the "Embedded Binaries" section, building the file lead to the error:

dyld: Library not loaded: @rpath/libswiftAppKit.dylib
  Referenced from: ~/Library/Developer/Xcode/DerivedData/zmq_cli-fqonwoqaewoenhdmsspynhszpsrt/Build/Products/Debug/SwiftyZeroMQ.framework/Versions/A/SwiftyZeroMQ
  Reason: image not found

I've also tried, to no avail, the advice from here and here and here. Is there a way to incorporate this library into a command line only tool? Thanks!

If i use c++ publisher send a char[] data to ios subscriber and receive data with recv(), it can not receive data correct.

My data is char[0] = -1. And i suppose it relate to "String.Encoding.utf8" in the recv() method