Re: WaitForSingleObject

From:

"Larry" <dontmewithme@got.it>

Newsgroups:

microsoft.public.vc.language

Date:

Fri, 29 Jan 2010 10:37:48 +0100

Message-ID:

<4b62ac6c$0$826$4fafbaef@reader5.news.tin.it>

"Ulrich Eckhardt" <eckhardt@satorlaser.com> ha scritto nel messaggio
news:i5ia37-kp1.ln1@satorlaser.homedns.org...

This looks much better, it makes the association immediately clear.

// CALLBACK EVENT
WaitForSingleObject(eventi[threadid], INFINITE);

Wait:
1. Access to 'eventi' is not inside a critical section.
2. You could simply use 'hevent'.

  if(users[threadid].cb.at(0).flag == BUFF_DONE)
  {
   string line = (char*)users[threadid].cb.at(0).data;

Similarly, access to 'users' is not guarded here!

I think the following should be a little better...

while(1)
{
  // CALLBACK EVENT
  WaitForSingleObject(hevent, INFINITE);

  EnterCriticalSection(&users_mutex);
  int flag = users[threadid].cb.at(0).flag;
  string line = (char*)users[threadid].cb.at(0).data;
  LeaveCriticalSection(&users_mutex);

  if(flag == BUFF_DONE)
  {
   int ret = s->SendBytes(line + CRLF);
   if(SOCKET_ERROR == ret)
    break;
  }
}

There is one easy fix: Create a single map from thread-ID to the shared
structure of both threads. The shared structure contains both the IO
buffers and the event to wake up the consumer. The consumer is also
responsible for creating the entry when it's ready and removing it when
finished.

Ok. I will consider that.

thanks