zeromq doesnt work when used as an indicator , but works when used as a script

[camjones.au]

Hi coders

I need to plot values from an EA onto a chart , It is a very complicated EA , and I want to do this for troubleshooting purposes , I have multiple signal setups and need to validate the signals/indicators 'look' correct visually [ie if signal1 is true plot arrow , if signal 2 is correct fill an area etc , up to 30 signals]. 

I want to use zeromq that pubs and subs , so that I don't have to use the indicator all the time , just when i am troubleshooting.

I downloaded 2 scripts that work as examples of how to use zeromq. They work as scripts , i put one one server script on one chart and used the client script on another.
Ther server publishes data to port 5556 , the receiver subscribes to port 5556 and reads the data. These scripts work fine.

I have a need however to use zeromq as a indicator , that needs to plot information on the graph on each bar. So I want to convert the receiver code to become an indicator. 
I have pasted and slightly modified the client code into an indicator called 'plottest'. I am using basic print to debug and without plotting as yet.

The indicator when added to a chart locks up MT4.

If i change this line of code from this

"subscriber.recv(update);"

to this

"subscriber.recv(update,1);"

 the code runs but no data is returned. [I am a newb at zeromq/mt4, but I read somewhere this is a noblock flag change]

If i change the line to

Print(subscriber.recv(update,1));

it returns false , so it is not reading any data.

Seems I am missing something obvious? like this is never going to work... or i got some brain malfunction.
Any ideas?

What do other people use to validate signals? I don't want to put on 30 indicators at once because it would be unreadable. My signals are linear , once a signal is activated it waits for another/new/different signal [its/I am complicated]. This zeromq would solve my issues for ever but I cant get it to work.

Regards
Cam

snippet below from plottest.mq4

//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
  {
//---

Context context;
int InpZipCode=10001;
//  Socket to talk to server
Print("Collecting updates from dodgy weather server…");
Socket subscriber(context,ZMQ_SUB);


   
subscriber.connect("tcp://*:5556");
subscriber.subscribe(IntegerToString(InpZipCode));



//  Process 100 updates
int update_nbr;
long total_temp=0;
for(update_nbr=0; update_nbr<100; update_nbr++)
  {
      ZmqMsg update;
      Print(subscriber.recv(update,1));
      string msg=update.getData();
      if (msg!=""){
      Print(msg);
      }
  }
return(rates_total);
}

[camjones.au]

mmm update.


I have a workaround , but I don't prefer it , though it is simpler , yet not as 'adaptable to everything'.

see https://www.mql5.com/en/forum/244357/page2

 at post 16 by @nicholi shen

Simple code. my example is attached below as files , compile and both the EA [EATestPlotTest2] and the Indicator [plottestv2] to the same chart.

Be nice to know why I couldn't use ZeroMQ in an indicator though.

18hrs of my life gone.

Cheers
Cam