[lwip-users] UDP sendto() blocking

[aparna.dutta]

 

 

We are using Lwip ported onto the Analog Devices VDSP++ 4.5 (Blackfin family , Feb 2007 update) to implement an RTSP/RTP streaming server.

 

To send RTP packets using UDP, we are creating a socket of type SOCK_DGRAM, and then using sendto() to transmit the RTP packets. After sending some packets, the sendto() function blocks, and the RTP thread hangs pending for a semaphore.

 

We tried to change the socket to non-blocking mode, but it does not seem to have any effect.

 

Unlike a TCP connection, UDP does not have flow/congestion control and does not need to wait for ACKs from the receiver. Then what does the UDP sendto() function wait for?

 

Thanks and regards,

Aparna