Re: tcpstream write() weirdness

[David Sugar]

The stream classes require implicit flushes because you are writing to the 
internal stream buffer first, and then real writes occur.  This can be 
done with << endl or by implicity calling flush().

On Thu, 21 Nov 2002, Ari Johnson wrote:

> 
> I'm using tcpstream (for simplicity) in a multithreaded app, and am
> protecting all read() and write() calls on it with a mutex.  I am able to
> write to the tcpstream once and read the server's response, but the next
> write() call simply never gets sent out to the network.  Is this a known
> issue?  Many times I've banged my head off of walls trying to figure out
> why something won't work for me, only to have a mailing list inform me
> that I was doing something that I shouldn't, so I wonder if that's not the
> case here.  Below, find a basic idea of what my class hierarchy looks
> like; and thank you to any who reply.
> 
> Ari Johnson
> 
> --
> 
> class Stream : public Mutex {
> private:
>   tcpstream tcp;
> public:
>   void read(...) {
>     while(!tcp.isPending(Socket::pendingInput, 1000)) {
>       if(tcp.isPending(Socket::pendingError, 0))
>         throw something;
> 
>       Thread::yield();
>     }
> 
>     enterMutex();
>     tcp.read(blah, len);
>     leaveMutex();
>   };
> 
>   void write(...) {
>     enterMutex();
>     tcp.write(blah, len);
>     leaveMutex();
>   };
> };
> 
> class Incoming : public Thread {
> private:
>   Stream *stream;
> public:
>   void run(void) {
>     while(1) {
>       stream->read(somewhere);
>       possibly_tell_Outgoing_to_send_something;
>     }
>   };
> };
> 
> class Outgoing : public Thread {
> private:
>   Stream *stream;
> public:
>   void run(void) {
>     while(1)
>       if(feel_like_sending_something)
>         stream->send(something);
>   };
> };
> 
> NB: Incoming and Outgoing are created in pairs, and the pair shares a
>     single Stream object.
> 
> 
> 
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