MaX <[email protected]> wrote:
> I'm looking to the netconn interface and I don't completely understand the
> semantic of the netconn_write.
> The signature of the function is:
>
> err netcon_write(struct netcon * aNetcon, void* aData, size_t, aSize, u8_t
> API_Flags);
>
> With the NETCONN_NOCOPY flag, the data should remain unattached until it has
> been transmitted.
> Therefore, what mechanisms can I use to know when a sent buffer can be reused
> in a safe way?
TCP has to keep data buffer for retransmission until it is ACKed by the remote
host. There'd ere, it needs to maintain unchanged for a while. You can either
pass *static* data to netconn_write (NOCOPY), or tell netconn_write to copy
data into internal buffers. However, this means extra memcpy plus extra buffer
allocation (up to the amount of the TCP window).
Simon
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