Having a tough time learning ASIO. I'm trying to have one thread constantly
listen for new file monitoring events (mthread) while another thread
processes one task at a time (wthread). Somehow I'm still losing events
that don't get placed on the task_queue and it would seem that once an
event is lost, the file_handler callback for the dir_monitor stops working
thereafter for good. So I'm having a few issues with my solution.
If I comment out the sleep() method below, then for some reason the first
two lines that have to do with the dir_monitor immediately after the while
loop quickly eat through all available memory and the program will soon
crash within a minute or two. Leaving the sleep in keeps things stable, or
maybe it just eats away so slowly I don't notice it.
Leaving sleep() in also has the problem of *I think* causing missed file
events. The f_handler() function posts tasks that I create within the
dir_monitor callback back to the main thread via the io_service.post(), but
if its asleep, will it be able to place objects on the main processes
task_queue? I think thats one point where I'm going wrong.
If anyone sees where I'm going wrong, any help much appreciated.
---
static queue task_queue;
boost::asio::io_service io_service;
void queue_task(TaskObj *task)
{
// pass task back to main thread.
task_queue.push(task);
}
void f_handler(const boost::system::error_code &ec, const
boost::asio::dir_monitor_event &ev)
{
TaskObj task = new TaskObj(...);
// create task and place on queue by posting to main process
io_service.post(boost::bind(queue_task, task));
}
int main(...) {
boost::asio::io_service work_service;
boost::asio::dir_monitor dm(io_service);
dm.async_monitor(f_handler);
// dir_monitor thread
boost::thread mthread =
boost::thread(boost::bind(&boost::asio::io_service::run,
boost::ref(io_service)));
// setup work to prevent premature exit
shared_ptrboost::asio::io_service::work
work(new boost::asio::io_service::work(work_service));
// worker thread
boost::thread wthread(boost::bind(&boost::asio::io_service::run,
boost::ref(work_service)));
wthread.detach();
while (true) {
io_service.reset();
dm.async_monitor(f_handler);
// losing all available memory from above two lines without the
sleep() below
// get first task off of queue and process in worker thread
task = task_queue.front();
// functor executed in seperate thread
work_service.post(boost::bind(&TaskObj::do_it, task));
sleep(3);
}
