Blog: 2025-02-23

Fun with the gcc compiler and linker

hack $ gcc-14 -L /usr/local/lib/ -I /usr/local/include/ -Wall -Werror -l zmq hwserver.c -o hwserver
hack $ ./hwserver

Some sockets with the zmq

-- hwclient.lua
local zmq = require "zmq"

local context = zmq.init(1)

local socket = context:socket(zmq.REQ)
socket:connect("tcp://localhost:5555")

for n=1, 10 do
  print("Sending Hello " .. n .. "...")
  socket:send("HIIII -lua")
  local reply = socket:recv()
  print("Received " .. n .. " [" .. reply .. "]")
end

socket:close()
context:term()

// hwclient.c
#include <zmq.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>

int main() {
  printf("Connecting to hello world server...\n");
  void *context = zmq_ctx_new();
  void *requester = zmq_socket(context, ZMQ_REQ);
  zmq_connect(requester, "tcp://localhost:5555");

  int request_nbr;
  char outgoing[8];
  for (request_nbr = 0; request_nbr < 10; request_nbr++) {
    char buffer[10];
    printf("Sending Hello %d...\n", request_nbr);
    sprintf(outgoing, "Hello %d", request_nbr);
    zmq_send(requester, outgoing, 10, 0);
    zmq_recv(requester, buffer, 10, 0);
    printf("Received World %d\n", request_nbr);
  }

  zmq_close(requester);
  zmq_ctx_destroy(context);
  return 0;
}

// hwserver.c
#include <zmq.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>

int main() {
  void *context = zmq_ctx_new();
  void *responder = zmq_socket(context, ZMQ_REP);

  int rc = zmq_bind(responder, "tcp://*:5555");
  assert (rc == 0);

  while (1) {
    char buffer[10];
    zmq_recv(responder, buffer, 10, 0);
    printf("received %s\n", buffer);
    sleep(1);
    zmq_send(responder, "world", 5, 0);
  }

  return 0;
}

and in ~/.profile:

export LUA_CPATH="/usr/local/lib/lua/5.4/?.so;$HOME/.luarocks/lib/lua/5.4/?.so"

Links:

• https://github.com/booksbyus/zguide/tree/master/examples
• https://zguide.zeromq.org/docs/chapter1/