[lwip-users] How do I check if a packet is sent out?

[Chen]

Hi, all,

In my project, I need to send out an UDP packet then stop the system
interrupts for a few ms, but I need to confirm the UDP packet is sent out
first (I don't need to confirm if it will reach the 
destination)

I send out the UDP packet using 

lwip_sendto(lSocketUDP,
myudpout.buffer,
sizeof(myudpout),
0, (struct
sockaddr *)&sSyncDestAddrUDP,
sizeof(sSyncDestAddrUDP));

How can I confirm *THIS* packet is sent out?

Can anyone be so kind to give me a pointer?

Thanks

Chen

BTW, I also have an active TCP connection at the same time