The Qt license question
 

With Qt library you can develop opensource without paying the license. If you want to develop commercial application, you have to pay the license....

Ok, what about this:
I want to develop commercial applications using Qt. So to avoid paying the license, I make it opensource. But I sell it to company, people, government ( you name it ). I forbid every one to use my program without paying money to me but my program is opensource. Is this possible? Is this legal?

Nope.
Once you put a restriction like that on it , it's not Open Source.

well, then you are coding a commercial open source application,
I don't see why an open source app cannot be commercial, All the time you sell it with the source code.

i think the qt license is for GPL apps?

So according to you, except for forbidding people for using my program free of charge, it is legal to code opensource commercial application without paying the license. Well, maybe the only downside for this style is everyone can download the source dan build it, then use my program without paying money to me. And they can sell it to others.

Is that right????

That is correct.

But the idea is that you don't make money by selling the app, you make money by selling manuals, technical support, and nice box sets that save people the bother of compiling it themselves. This is how the commercial distributions work.

And if you fear that you will lose out significantly if a competitor undercuts you on price by stealing your work, then you can just buy a qt dev license from Trolltech and release your product closed source.

If you expect to make any significant amount of money out of selling your program, just buy a Qt licence, it's not all that expensive.

Alex

The GPL allows you to sell your program for whatever price you wish. Read it first :)

Yeah, and people have option to use your program free of charge......

Just put a copyright in your code and don't use the GPL.

It's important to differentiate between open source development and open source distribution. An open source development project is owned by the community. If you chose to openly distribute your individual work as source code however, you still own it and RMS can't stop you from placing whatever restrictions you like on it. The GPL borrowed the open distribution aspect of shareware licenses and added the community development model to it (the bazaar.)

As to Qt, if you intend to distribute their libraries with your commercial app, you should pay them their money.

I think an important distinction that many are missing here is that the GPL is an open source license. However, it's by no means the only open source license. Open source doesn't necessarily mean GPL, or free as in beer...

Here we go again ;)

--Shade

Shade is correct. You can have an open source license that is different from the GPL. You can also have open source licenses which are commercial and restrict re-distribution (even to the point of it being only transferable to a person who buys the license,... don't know how you'd enforce that though). Doing that may make it incompatible with other licenses though. Open Source means you can look at the source code (to modify it, etc.). It doesn't neccesarily mean that you must give away the program.

You can also have free software that is closed source. Many libraries are essentially commercial, proprietary programs that you can give away under certain conditions.

The following is a quote from qgpl of wich the free trolltech component is licend under, oh it is a split license, the other license is GPL

"a. You must ensure that all recipients of machine-executable forms of these items are also able to receive and use the complete machine-readable source code to the items without any charge beyond the costs of data transfer.

b. You must explicitly license all recipients of your items to use and re-distribute original and modified versions of the items in both machine-executable and source code forms. The recipients must be able to do so without any charges whatsoever, and they must be able to re-distribute to anyone they choose. "

So no you can not horde the software without paying a license to trolltech.

If you choose to keep you software no libre then the price (for a single developer) is :
$ 1550 professional Edition
$ 2490 Enterprise Edition