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IPC - Sending and Receiving

  • server at port 1234 and client with handle opened to server 
    q)// server
q)\p 
1234i

q)// client
q)h:hopen 1234
q)h
3i

Sync Send and Receive

  • Synchronous message: client sends the message and blocks the handle until servers sends a response
  • To send a message we can use "string" format along with handle h 
    //client
q)h"2+2"
4i
q)h"g:23"
q)


//server
q)g
23
* Messages can also be send in functional form - handle(function;arg1;arg2;..;arg n) 
//client
q)h(+;2;2)
4i
q)h(set;`abc;245)
`abc

//server
q)abc
234
* For assigning value in functional form we use variable name as symbol or we can use function name as string * We can also execute functions defined in server side from client 
//server
q)f:{x*x}
q)f
{x*x}

//client
q)h(`f;2)
4
q)h("f";2)
4
* we can also send client side function to server along with arguments and get the results with server running the execution 
//client
q)f2:{x-y}
q)h(f2;45;23)
22

//server
q)f2
'f2
  [0]  f2
       ^
* we can get data from server using get function or using variable name directly which exists in server 
//server
q)list: 1 2 3 4 5

//client
q)h(get;`list)
1 2 3 4 5
q)h(get;"list")
1 2 3 4 5
q)h"list"
1 2 3 4 5
q)h("list")
1 2 3 4 5

.z.pg

  • message handler function for handling synchronous messages
  • executes everytime process/server receives synchronous message 
    //server
q).z.pg:{0N!value x}
q)13

    //client
q)h"2+3+8"
q)13

Async Send and Receive

  • client doesn't wait for server to send the response, it continues its execution
  • to send a async message we use negative handle
  • Sending async messages does not send the message immediately. It serializes x, and queues it for sending at a later time - either when the main loop spins, or a blocking request is issued on that handle
  • .z.ps async message handler 
    //client
q)(neg h)"2*5"
q)(neg h)(+;2;5)
q)(neg h)"mko:908"
q)h"" // to ensure async messages queue is processed
q)(neg h)[] //used to flush the queue

    //server
q)mko
908
  • To confirm async messages are received and processed, chase with sync message q)h""
  • To block until all pending outgoing messages have been written into the handle 
    q)(neg h)[] //or 
q)(neg h)(::)
  • if we want to ensure an async message really has been sent as soon as possible, use: 
    q)(neg h)"x";
q)(neg h)[];
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