C# TCP Application deadlocks on one computer and never deadlocks on another

Question

I'm not sure how to approach this. I am hesitant about showing my code because it's a university assignment. I need some place to start.

I'm making a TCP card game with four players and a server. Every 100ms, a player asks for an update from the server using a background worker. The server accepts a client connection and reads in a Enumeration value (sent as an Int32) that tells it the action it wants server to send it (update, card, player, etc) and a value that is read in based on the Enumeration value (Recieving an Update Enumeration means it needs to read in a Int32 next). The server sends back a response based on the Enumeration read in.

Here's where the problem occurs. I have a custom built computer (2500K processor, Win8 x64) and when I execute the program on it, it will loop forever, accepting client requests and sending the appropriate response back. Exactly as expected! However, on my laptop (Levono YogaPad, Win8 x64) the back and forth exchange lasts for around 30-50 requests and then deadlocks. It's always at the same spot. The server has read in the Enumeration and is awaiting for the second value. The client is past the part of sending the enum and value and is waiting for the results. It is always stable on my desktop and always deadlocks on my laptop. I even slow the program down to update every second and it still deadlocks. I'm not sure what to do.

I've built the program on each computer. I've built the program on my desktop and ran it on my laptop and it still deadlocks. Does anyone have any suggestions?

Many thanks!

Answer 1

You are lucky that the code hangs on one machine before you send the assignment in and it hangs on your teachers machine. You are also lucky that the problem is reproducible, so better find out where exactly it hangs. Without having access to the code I have the following wild guesses:

• you forgot to do proper error handling in all places and now it busy loops because of an unexpected error
• it hangs inside a read where you try to read N bytes but the peer sends only K<N bytes

These are wild guesses, but without having access to even the basic structure of your program you cannot probably expect anything more.