Re: [lwip-users] Freeing memory after http transfer

[address@hidden]

Bernhard 'Gustl' wrote:
> tcp_write is used in my copy too.

Of course it is. The question is whether you pass TCP_WRITE_FLAG_COPY or 
zero as 4th argument to tcp_write(). If you pass TCP_WRITE_FLAG_COPY, 
data is copied from the pointer you pass to internal buffers which are 
freed when ACKed. If you pass zero, data is sent directly from the 
pointer you supplied ("zero copy").

In the first case (FLAG_COPY), you can free your buffer after passing it 
to tcp_write(), whereas in the latter (zero), you have to keep the 
buffer unchanged and allocated until the accumulated count from 
http_sent() tells you all data has been ACKed.

I don't know whether the version of httpd from 1.3.0 does this correctly 
or not, but what I do know is that it did have bugs at that time and 
should not be used in production environment without further testing (it 
was meant as an example application then). However, I'm in the process 
of hardening the httpd as I do want to use it in production environment, 
so you are still having problems with httpd from CVS head, please let me 
know.

Simon