Qt - A few general questions

  • Ok I think I'm getting the hang of this... Sorry for all the simple questions but I have been searching and have found some answers but not all:

    1. Qt community - Am I understanding this correctly that there is no license fee or anything with respect to use? Initially I need to develop software for my client to control an instrument test bed. This software will go no further than their lab and be used by one or two people at most to debug hardware. It looks like community has everything I need for this BUT am I within the constraints of the license?

    2. Windows/Mac - My current project needs to run under Windows. Is there any reason I cannot port it to Mac when I desire? IE download an install community edition for mac, copy over the code, compile and make minor corrections?

    3. Compilers - I have a full blown VS2013 professional installed. Right now my community version is using that for 32 bit (a current requirement due to computer hardware) builds. All seems well and happy. I don't want to start a compiler war but is this a reasonable choice? I see there are make definitions for MinGW, g++ and some others. Recommendations?

    4. Add ons - It seems like Qt has so much and probably more than I'll need. However is there a resource or repository where developers are offering or selling libs and add-on's they've created for use within Qt? For example I am pretty sure I'll need some kind of TCP client/server. While I could (and have) rolled my own in the past and I know that Qt has modules are there public offerings I can find that would save time (and perhaps money) for things like this?

    5. Probably a dumb question - I'm probably going to need to make use of some C++ libs. One in particular is the FTDI D2XX drivers for direct com with FTDI usb interfaces. Our electrical guy loves these drivers but he uses Visual Basic. In general (say comparative to other implementations...) is it pretty straight forward to get these linked in? I'm sure this depends upon the lib (I know FDTI has .h and DLL that are compatible with c++). Anyone using these drivers?

    Thanks for the help. I do appreciate the time people take to answer.

  • Hi,

    1. If you don't statically link your application but use shared libraries, Qt Community Edition is OK. "This":http://www.qt.io/qt-licensing-terms/ page may be helpful.

    2. Unless you use platform-specific APIs, you shouldn't have any problems recompiling your Qt project on another supported desktop platform. Don't forget to check the platform-specific notes in Qt documentation: http://doc.qt.io/qt-5/gettingstarted.html#platform-requirements

    3. VS on Windows is just fine. Qt Project provides prebuilt binaries for several VC++ configurations.

    4. TCP support in Qt Network module is great. No need for any 3rd party component for networking unless you need an HTTP server. But if you need SOAP, you can look at KDSOAP. Also you can look at KDE Frameworks 5 - Tier 1 and Tier 2. QWT is a nice plotting library. You may find http://inqlude.org useful.

    5. Haven't used that.

  • Lifetime Qt Champion


    1. The only good answer is check with a lawyer: but like ckakman suggested, take a look at the matrix and licensing pages. To be really sure you are doing the right thing, ask the Qt Company directly.

    2. Nothing to add

    3. Use the compiler you like the most, nothing wrong with it. Just keep in mind that it's best to have all libraries compiled with the same compiler.

    4. IIRC There should be something like QHttpServer for QtCloudServices

    5. If you are using the device as virtual com port you can use QSerialPort. On the other hand, if you need to use it directly you can write you own QIODevice that talks with the device. However beware, the latest versions of OS X now include a driver for FTDI so it's seen directly as a serial port.

  • Thanks for the input.

    I will research the legal aspects and make sure we are on track.

    on the FTDI yes both Mac and Windows will see them as a comport but with the D2XX drivers you bypass that and there are some good reasons to do so for example you can better identify devices using the driver.

    The test bed/project will end up with a fair number of USB virtual com ports and some direct USB devices which will require the D2XX driver.

  • Lifetime Qt Champion

    Then just beware of the new driver from the the latest OS X version. AFAIR the unix version doesn't allow to work with either mode like on Windows

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