-----Original Message----- From: Kieran Mansley [mailto:[EMAIL PROTECTED] Sent: 20 March 2007 16:12 To: Mailing list for lwIP users Subject: RE: [lwip-users] Installed the new version, since allthechangesandturned on the ASSERT debug
On Tue, 2007-03-20 at 15:45 +0000, Joolz [RSD] wrote: > Do I need to free the data, I thought that would be done by the > udp_send >From doc/rawapi.txt: >>- err_t udp_send(struct udp_pcb *pcb, struct pbuf *p) >> Sends the pbuf p. The pbuf is not deallocated. >>udp_send() can't free it for you as it has no idea how you allocated it. >>For example, the pvMalloc() call above was used to create the payload area, but lwIP has no idea how to do the opposite of that to release the memory >>you've used. >> What I meant was the header buffer it creates, not my data allocation. When I send the first packet I see that data->payload now has a pointer and data->len is now 44, overall length is (7*188)+44, I would have thought that this would be back to 0 and 7*188 after the send. >>One other thing that concerns me about the above is that it suggests that you are assuming that by the time the udp_send() call returns, there will be no >>further need to access the memory you passed in. >>Depending on your hardware, and the driver that sits underneath lwIP, this might not be the case. lwIP has finished with it, but the driver might not have got >>it onto the wire yet. However, there's no visible way to find out when it is safe to free the memory for UDP. For TCP we have the "sent" callback. So not a >>lot you can do about that, but worth being careful and making sure it's not a problem for you. >> >>Kieran I am pretty sure that the data will be available as I said before the buffer is 512K and for this to wrap around before a packet is sent should not happen. _______________________________________________ lwip-users mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/lwip-users _______________________________________________ lwip-users mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/lwip-users
