Re: Using luasocket to read from the keyboard

[Nick Gammon <nick@...>]

On 08/06/2008, at 5:08 PM, Diego Nehab wrote:

> LuaSocket uses recv/send instead of read/write. The posix
> manual says they are equivalent if no flags are used, which
> is LuaSocket's case. On Windows, however, this will never
> work.

Hi Diego,

Thanks for responding. :)

I didn't really expect it to work on Windows, as they tend to fudge  
things around a bit regarding sockets/files, however I had more hope  
under Linux.

My code for reading from the socket, in my C program, was:

  // check for input on our socket

    if (FD_ISSET (s, &in_set))
      {
      int nRead;

      nRead = read (s, buf, sizeof(buf) - 1)

  // and process buf ...


And for the keyboard:

    // check for input on the keyboard

    if (FD_ISSET (STDIN_FILENO, &in_set))
      {
      int nRead;

      nRead = read (STDIN_FILENO, buf, sizeof(buf) - 1);

So basically it was the same, and it worked (I think) regardless of  
how much you typed. Maybe the keyboard buffered a line, but then you  
only got the "select" notification when something was there.


> On the other hand, stdin is probably set to blocking mode,
> so when there is nothing available, it recv will block until
> all the data you need shows up. Also, keyboard input will be
> buffered until you hit return, I guess.

In my C program I don't think I turned blocking off at all.

> If you really want to use keyboard:receive(), you have to
> call setfd on a *connected* socket. The socket returned by
> socket.tcp() does not support the receive method.

Ah, you mean make some sort of dummy connection, and then switch FDs?  
How would that work?

----

Just out of curiosity, is there some sort of limit on simultaneous  
connections? I am writing a stress-test application using luasocket,  
to test out a MUD server. Despite it successfully making 200  
connections with no asserts, only 65 players ever seem to be active.  
It is almost as if only the first 65 ever get reported by select. But  
maybe it is a server-side problem. Just asking in case you say "oh  
yes, we limited it to 65 connections".

- Nick