Is there any open C/C++ source code available for enforcing user licenses?
That source code must have mechanisms to ensure that:

1. Users cannot run simultaneously more copies of the tool than those that they have purchased.
2. Users can not use the tool after the license period expires.

Thank you in advance

This is open source. The very intention is not to enforce anything. Why would you even consider that?

If you want to hide your code, then create a binary-only file for others to use, like some of the CAD programs that are available for Linux do.

But don't expect support in this endeavor. Open source is just that: Open source code.

Well spoken, indeed. You can write proprietary software for Linux if you want to, but it won't be very kindly accepted. You'll also need to find your own way around the General Public License, which won't be possible if you're using GNU/GPL tools to create your software.

Cheers

This is not true. Only if you want to re-distribute or bundle such tools or libraries you may have an issue.

/don't trust forum advice including this post itself

Say what ?. The previous post was over 13 years ago.

Long dead and buried and no one would care any more.

"/don't trust forum advice including this post itself" said avalonit.

Even though, yes, the original post is very old, I still believe that the best "software license enforcement" is: "none, other than expiration dates."

I've sold a proprietary Windows product for more than twenty-five(!!) years now, and the only thing that it has is a simple serial-number that can have an expiration date. There is no "enforcement." I don't want my paying customers to even be inconvenienced. I use the expiration-date feature to support time-limited (but not feature-limited, and not "free") trials ... and to offer an attractive low-priced option for a frequently occurring use case. (You can apply the full purchase amount of a time-limited version toward the purchase of a not-time-limited version during the time-limit period.)

I don't lose sleep over the license-code-publishing that I know happens. I'm too busy supporting my customers. And, "leaving them with a stack of virtual business cards ..."

One very interesting thing that I did learn is that some government customers, particularly outside of the USA, need for there to be "something that they must buy." Because they're not allowed to spend public funds for anything that can be had for free, and they don't feel comfortable trying to satisfy their auditors unless there's a license-code that they can point to. I guess that's at least part of why many [business ...] products that are "off the [now-virtual] shelf" often still require the entry of some "code" at some point during their installation . . .

Thanks for the answer! Do you use any ready library for license enforcement or you custom-coded it?

P.S. for people complaining about answering old posts, this is my reply http://rboci.blogspot.com/2017/12/wh...cromancer.html

I'll gladly pay for killaware, IF I can have the source ;-)
Never afraid to pay for a persons work...as long as I can supervise from start to finish

The original (very old) question.
"Is there any open C/C++ source code available for enforcing user licenses"