I have just installed Fedora Core 2 on my notebook (HP NC6000) and have written a little software in C (GNU / GCC) to communicate with a network device. A TCP/IP device that decodes DVD data.

I noticed that the streaming of my data is not smooth and when I checked the ifconfig eth0, I found that there has been massive amount of collisions.

I am very new to GCC C development and have close to nothing about Linux. My question is
1) How do I go about determining collisions of packet during a send() or write() command.
2) How do I go about checking if my send() buffer has been read by the other end?

** It worked fine when I was using the same code in CYGWIN Windows version.

My questions may should somewhat silly to many, but I do hope the "gurus" out there would excuse a newbie.

Thank you in advance for the help and advice.

ArtemaTalento.

1. You can't do anything just changing your code. Collisions happen on a lower level than your code. When there are collisions it doesn't mean your data does not arrive to the other end (it may take it more time, through). Making the whole thing very simple collisions happen when there's too much traffic in the network. If such situation happen, there's an automatic retransmission.

2. I'm not 100% sure (should look into the code), but if you're in blocking mode, you have the result as return code.

BTW When it's about media, maybe UDP is a better idea for you than TCP?

Throw away the hub, buy a switch.

Thank you for the reply.

I am using TCP mode as my connection mode. I have not set blocking mode as I did not know the usage and functionality of blocking. What it does and it's reason of usage. In fact, the only error trapping I did was to determine if my send() function was working.

if (send(phSocket, szBuffer, 1460,0) <=0) printf("ERROR %d\n", errno);

Is there any site or reference where I can read about blocking mode and how I go about doing it?

Thank you again for the reply and much needed help.

Your code to find errors was OK. It looks that your send() operations work.

Can't find any good link about blocking and non-blocking sockets. By default the socket is blocking, you make it non-blocking using something like .

Thank you very much for the reply. I am still trying to get things working and is now looking at the possibility of using libpcap (if that can help).

I shall post my findings when I have manage to solve it.

Once again, thank you and regards.