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Re: [lwip-users] netbuf_data() netconnwrite() problem
From: |
Francois Bouchard |
Subject: |
Re: [lwip-users] netbuf_data() netconnwrite() problem |
Date: |
Tue, 17 Feb 2009 10:57:37 -0500 |
> The other thing that makes me slightly nervous is the use of
> NETCONN_NOCOPY. How/when are you freeing inbuf?
I'm doing a netbuf_delete after each receive. Grosso modo:
inbuf = netconn_recv(conn);
if (no errors)
netconn_write()
else
netconn_close()
netbuf_delete(inbuf);
> How is the client sending the ushorts? If it does, for example, 10
> separate writes, you might receive them as 10 separate receives. This
> might explain why a string works and the ushorts don't as I'd expect the
> client to send the string in a single write. Of course if you're using
> TCP the network stack is free to segment and combine application writes
> into whatever blocks it likes, so you can't assume that you'll receive
> the data in the same blocks it was sent in.
I'm not shure, the client test application uses SendBuf(void *Buf, int
BufSize, int Flags = 0) of VCL TBaseSocket lib, with Borland C++. I guess
its a single write.
Many Thanks,
PS. how suitable is the netconn_* API for multi-connexion socket?
Francois
----- Original Message -----
From: "Kieran Mansley" <address@hidden>
To: "Mailing list for lwIP users" <address@hidden>
Sent: Tuesday, February 17, 2009 6:39 AM
Subject: Re: [lwip-users] netbuf_data() netconnwrite() problem
> On Mon, 2009-02-16 at 14:42 -0500, Francois Bouchard wrote:
> > This code works for a string ie. it sends exactly the same thing. But
for
> > ushorts I can't manage them. Maybe I'll stick to strings ... and change
the
> > client test program.
>
> How is the client sending the ushorts? If it does, for example, 10
> separate writes, you might receive them as 10 separate receives. This
> might explain why a string works and the ushorts don't as I'd expect the
> client to send the string in a single write. Of course if you're using
> TCP the network stack is free to segment and combine application writes
> into whatever blocks it likes, so you can't assume that you'll receive
> the data in the same blocks it was sent in.
>
> The other thing that makes me slightly nervous is the use of
> NETCONN_NOCOPY. How/when are you freeing inbuf?
>
> Thanks
>
> Kieran
>
>
>
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