6 ms·

It's confusing as hell what you can actually do with it... Even talking to Qt sales, it is a little fuzzy on what is allowable or not. But in general yes, you

by radix07 10y ago

It's confusing as hell what you can actually do with it... Even talking to Qt sales, it is a little fuzzy on what is allowable or not. But in general yes, you can create commercial products as long as you don't modify their stuff or link to it improperly or look at it wrong.

joezydeco 10y ago
I'm a Qt developer with 10 years under my belt and I still can't figure it out. But something has radically changed with the new LGPL licensing in recent versions, from what I can tell. I recently received an RFP from a very large European vehicle manufacturer, the RFP requested that Qt 5.6 should be used and no later. (The licensing changed with 5.7, so their lawyers must have figured this out)
- radix07 10y ago
  That sounds concerning, I would really like to know more about what that really means. I briefly started investigating the changes for Qt 5.7 before I started having flashbacks of trying to figure out all this LGPL stuff again. Does not seem to be any less confusing...
  - joezydeco 10y ago
    My team didn't take the proposal, but from what I gathered during some fact-finding the 5.7 terms changed what you need to distribute to customers regarding the Qt libraries. Before, you had to maintain a Qt source repository that matched distribution. People could build and link in Qt as they pleased, either vanilla from that repo or modified as they liked. With 5.7 and the new LGPL, it seemed that you also have to provide the entire toolchain needed to build the source and link it into the final application. Which means you also need to provide the kernel headers and etc that match up. I could be totally wrong. But I'm guessing 5.7 required too much other stuff be made public and the customer wasn't pleased with that. Can't say I disagree.
    - slavik81 10y ago
      It's the same anti-tvoization stuff as GPL3. Companies were giving out the source code, but used locked down hardware or proprietary toolchains so the source code was useless. What LGPL3 specifies over LGPL2 is that the source code needs to actually be usable. The spirit of that rule rather makes sense to me. Of course, part of the reason why The Qt Company likes LGPL3 is that other companies are going to look at the requirements to use and distribute open toolchains for their supported platforms and just buy a commercial license instead.
      - joezydeco 10y ago
        The funny thing is that the Yocto project has kind of eliminated a lot of the hurdles. You could technically branch a .bb recipe for your kernel and boardset and everything else would build on its own, including the SDK with toolchain wrapped in. Qt seems to be almost caught up with getting qt5 in the meta directories and having everything in place.
- plq 10y ago
  Could that be rather because Qt 5.7 and later requires C++11? The automotive industry is notorious for hating to change what already works, after all.
  - joezydeco 10y ago
    Nope. I just pulled the RFP back up and it said, somewhat cryptically but explicitly, "Reason: Qt license changed with 5.7"
- mrpippy 10y ago
  5.7 dropped LGPLv2.1 as an option. LGPLv3 includes the "anti-TiVoization" clauses which require that any device including the software must include an offer for not only the covered source code, but "Installation Information" allowing the end-user to replace the firmware on the device. Giving out this info is not something that a car company (or really any companies) want to provide. It's unfortunate that a large car company doesn't want to buy a commercial license, but maybe they'll be forced into that once 5.6 becomes too old.
  - radix07 10y ago
    Yeah, for a large company I would think the license would have been nothing compared to paying the lawyers to investigate the LGPL changes.
    - heeen2 10y ago
      I think companies fear after they invest in a 5.7+ Qt stack, QtCompany can just ramp up their price after the initial contract runs out.
      - radix07 10y ago
        Yeah... A lawyer would never do that...
  - joezydeco 10y ago
    Can you clarify how that differed from the previous open-source license? I thought, prior to 5.6, you could go licenseless if you provided a way for the user to replace the (dynamically linked) Qt libraries with libraries of their own. Was it just too nebulous before, and most companies just didn't offer a way to do this or buried it in some backdoor or something? Yeah, I agree it's a shame that a lot of companies don't want to license up, but if you've seen what they want for a per-device fee these days you'd probably understand. I did a product in 2008 and it was maybe $1/unit, now it's an order of magnitude larger.
    - 10y ago
- distances 10y ago
  This sounds weird. Why wouldn't they require the commercial version of Qt to be used instead?
ihaveajob 10y ago
I've seen even legal departments get scared from some of these licenses, but it's not that complicated. GPL requires that you license ALL your code as GPL as well. LGPL lets you link against a so-licensed library without affecting the license for the rest of the software.

by radix07 10y ago

joezydeco 10y ago

I'm a Qt developer with 10 years under my belt and I still can't figure it out. But something has radically changed with the new LGPL licensing in recent versions, from what I can tell. I recently received an RFP from a very large European vehicle manufacturer, the RFP requested that Qt 5.6 should be used and no later. (The licensing changed with 5.7, so their lawyers must have figured this out)

radix07 10y ago
That sounds concerning, I would really like to know more about what that really means. I briefly started investigating the changes for Qt 5.7 before I started having flashbacks of trying to figure out all this LGPL stuff again. Does not seem to be any less confusing...
- joezydeco 10y ago
  My team didn't take the proposal, but from what I gathered during some fact-finding the 5.7 terms changed what you need to distribute to customers regarding the Qt libraries. Before, you had to maintain a Qt source repository that matched distribution. People could build and link in Qt as they pleased, either vanilla from that repo or modified as they liked. With 5.7 and the new LGPL, it seemed that you also have to provide the entire toolchain needed to build the source and link it into the final application. Which means you also need to provide the kernel headers and etc that match up. I could be totally wrong. But I'm guessing 5.7 required too much other stuff be made public and the customer wasn't pleased with that. Can't say I disagree.
  - slavik81 10y ago
    It's the same anti-tvoization stuff as GPL3. Companies were giving out the source code, but used locked down hardware or proprietary toolchains so the source code was useless. What LGPL3 specifies over LGPL2 is that the source code needs to actually be usable. The spirit of that rule rather makes sense to me. Of course, part of the reason why The Qt Company likes LGPL3 is that other companies are going to look at the requirements to use and distribute open toolchains for their supported platforms and just buy a commercial license instead.
    - joezydeco 10y ago
      The funny thing is that the Yocto project has kind of eliminated a lot of the hurdles. You could technically branch a .bb recipe for your kernel and boardset and everything else would build on its own, including the SDK with toolchain wrapped in. Qt seems to be almost caught up with getting qt5 in the meta directories and having everything in place.
plq 10y ago
Could that be rather because Qt 5.7 and later requires C++11? The automotive industry is notorious for hating to change what already works, after all.
- joezydeco 10y ago
  Nope. I just pulled the RFP back up and it said, somewhat cryptically but explicitly, "Reason: Qt license changed with 5.7"
mrpippy 10y ago
5.7 dropped LGPLv2.1 as an option. LGPLv3 includes the "anti-TiVoization" clauses which require that any device including the software must include an offer for not only the covered source code, but "Installation Information" allowing the end-user to replace the firmware on the device. Giving out this info is not something that a car company (or really any companies) want to provide. It's unfortunate that a large car company doesn't want to buy a commercial license, but maybe they'll be forced into that once 5.6 becomes too old.
- radix07 10y ago
  Yeah, for a large company I would think the license would have been nothing compared to paying the lawyers to investigate the LGPL changes.
  - heeen2 10y ago
    I think companies fear after they invest in a 5.7+ Qt stack, QtCompany can just ramp up their price after the initial contract runs out.
    - radix07 10y ago
      Yeah... A lawyer would never do that...
- joezydeco 10y ago
  Can you clarify how that differed from the previous open-source license? I thought, prior to 5.6, you could go licenseless if you provided a way for the user to replace the (dynamically linked) Qt libraries with libraries of their own. Was it just too nebulous before, and most companies just didn't offer a way to do this or buried it in some backdoor or something? Yeah, I agree it's a shame that a lot of companies don't want to license up, but if you've seen what they want for a per-device fee these days you'd probably understand. I did a product in 2008 and it was maybe $1/unit, now it's an order of magnitude larger.
  - 10y ago
distances 10y ago
This sounds weird. Why wouldn't they require the commercial version of Qt to be used instead?

ihaveajob 10y ago

I've seen even legal departments get scared from some of these licenses, but it's not that complicated. GPL requires that you license ALL your code as GPL as well. LGPL lets you link against a so-licensed library without affecting the license for the rest of the software.