It depends on the contract that you had with the client. You might want to check Free Lance Switch. It’s a community of Freelance designers/coders. They might be able to help you out more.

@A_Wood is right: it certainly could depend on the contract.

Generally, if someone pays you to build/write something for them, they have some rights to it.

More than the legal sense, though, is the business sense. Your future business will come through referrals from your current clients. Why wouldn’t you want to give them what they want, and make them happy? If you don’t give them the source, they’re chained to you, which, understandably, could be a big problem for them.

I’m pretty sure that they’re planning on using someone else, but if I give away the source to the DLL, wouldn’t I be “giving away the farm” so to speak and the new designer can just use that DLL in all his own projects thereafter? I guess what I’m saying is that I invested a lot of time putting together this whole library of functions to help me do what I do more quickly, I’m very reluctant to just give it away to someone else that is possibly a competitor and give them an added advantaged that they didn’t have before. Just doesn’t seem right to me, that’s all.

@haken: That makes sense. I think the key is whether they paid you to build all these other library functions or not. If they did indeed pay you to build them as part of the project, then I think you have to release the code.

If it’s your own personal project that you just linked to, then it’s more difficult. You could try and make a binary of your library, and link to that, and release only the code you wrote for the client. However, if I were the client, I would be very unlikely to want to keep using some binary that a contractor supplied. What if they found a bug in the library? You can see how it’s a problem. Who would want to pay a contractor to write code that they could never use or alter if the person ever stops working for them?

I suspect your feeling that it will be a huge competitive loss to give up this code is also exaggerated. The amount of high quality code that’s currently available is amazing, and it’s still hard to do good original work. I’d just give up the code to the client and focus on building business from quality work and a good reputation.

@haken: Quite a bit depends on the terms of your agreement with them.

If you’ve agreed that you retain copyright in your work (which is not usually the case in work for hire), then you get to determine what happens with the DLL. This means that if they want to see the source code, you can put a license on it that says “You can use this in-house but not give it to anybody else.” This also applies if you wrote the DLL before your relationship with this company or independently of it—but if you go that route, you should really work with a good intellectual property lawyer to get the license correctly written.

You say “I’m pretty sure they’re planning on using someone else.” So what they want is to get the code of your DLL, so that they can give it to someone else to work with? My response to that would be, “I’m sorry, but that library of code is one of my competitive advantages, and so I won’t give it out for free. If you’d like to license it, I’m sure we could come to a reasonable understanding.”

Because, frankly, the main reasonable reason most companies would want to have copies of everything is business continuity in the case that you get hit by a bus. But this would be expressed by a desire for full source code upon delivery of the project, or by insisting on some source code escrow service, not by getting a copy of source at the inception of a project.

I NEVER give up the source code, they are buying the programming, I own the code.

@DrBill: depends on your contract with them. Look up “work for hire.” If they’re buying the programming, they own the code, unless you have an agreement that says otherwise.

My contract does specify that I own the code and they have a non exclusive licence to use it.