README

This is example code for an ML response.

client.c

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h> 

int main() {
	int a, c, s, r;
	struct sockaddr_in addr;
	char ping[5] = "PING";
	char pong[5] = "    ";
	
	#ifdef USE_SELECT
	fd_set reads;
	struct timeval tv = {1, 0};
	#endif

	memset(&addr, 0, sizeof(addr));
	addr.sin_family = AF_INET;
	addr.sin_port = htons(1234);

	a = inet_aton("127.0.0.1", &addr.sin_addr);
	if (a <= 0) exit(EXIT_FAILURE);

	s = socket(PF_INET, SOCK_STREAM, 0);
	if (s < 0) exit(EXIT_FAILURE);

	c = connect(s, (struct sockaddr *) &addr, sizeof(addr) );
	if (c < 0) exit(EXIT_FAILURE);

	write(s, ping, 6);

	#ifdef USE_SELECT
	FD_ZERO(&reads);
	FD_SET(s, &reads);
	while(select(1,&reads,NULL,NULL,&tv) == -1) {}
	#endif

	r = read(s, pong, sizeof(pong));
	if (r < 0)
		exit(EXIT_FAILURE);
	else
		printf("%s", pong);

	return EXIT_SUCCESS;
}

Rakefile

require 'rake/clean'

cc = 'cc'
cflags = %w[-ansi -pedantic]

file 'client.c'

desc "build client.out"
file 'client.out' => 'client.c' do
  sh cc, *(cflags + %w[-o client.out client.c])
end
CLEAN.include('client.out')

desc "build with select"
task :select => :clean do
  cflags << '-DUSE_SELECT'
end

desc "run server"
task :server do
  sh Gem.ruby, "server.rb"
end

desc "run client"
task :client => 'client.out' do
  sleep 0.5
  sh './client.out'
end

desc "run server and client"
multitask :run => [:server, :client]

task :default => :run

server.rb

require 'rubygems'
require 'eventmachine'

module Srv
  def receive_data(d)
    if d =~ /ping/i
      puts d
      send_data("PONG\n")
      close_connection_after_writing
    end
  end

  def unbind
    EM.stop
  end
end

host, port = '127.0.0.1', 1234
EM.run do
  EM.add_timer(5) { abort "server timeout" }
  EM.start_server host, port, Srv
  puts 'server ready'
end