I am a C++ novice. I have found an open source project written in C++/Qt. I want to make slight modifications and compile for both Windows and Mac. Is it typically that I will need to change my code to support either platform, or can it usually compile for both platforms out of the box?
If the source code uses clean C++ and Qt then it should compile (given that you have a Qt project file or Cmake file). If the code uses any platform specific APIs, you will have to update those first (either with multiple pieces of code, or with other cross-platform APIs)
In most cases, you don't have to change your code to support both OS s excepting cases described above. You simply have to open folder with ur qt project and open .pro file. The you should compile it and receive ur OS build.
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I have written windows gui application using qt and i want to deploy it.Now when i place .exe to other PC it shows error which says that qt5core.dll and etc required.I can install this dll,but is it possible to run exe app with qt without qt's dll as one file?So i can for example give .exe to my friend and he can instantly run it without installing .dll?
Basically, if you want a single exe file, you probably mean static linking.
The legal commercial version makes it possible or if I am not wrong, you will have to build a static qt version.
In the latter case, you will have to provide the source code of your application.
I do this sometimes, but you'll have to be careful with the license requirements: if you go with GPL, it should be OK, if you choose LGPL, it may be a bit less simple. No idea about the commercial version.
What you must do is building Qt statically, and then use that Qt build to build your application. I had a good experience with mxe. MXE builds an entire crossbuild environment and allows you to build your big Qt exe statically. I used it on Mac OS and Linux to build static executables for Windows, but you can probably run it on WSL. It takes a bit to compile, but it is simple to use. Please note that it cannot be used if your app needs QtWebEngine as it won't build with mingw.
Another simpler option is to create an installer. The Qt installer framework is simple to use. If you include the VS runtime, you end up with a single exe to distribute (the installer).
You always need to include the libraries you use (including your compilers runtime libraries in fact) when you deploy your executable - otherwise how would your application be able to use the code in those libraries? You may be able to statically link some/most things, but rarely everything. Look into how to create an installer / package for your application, so you can bundle up everything as one convenient file.
You can buid you app using QT Static (a large .exe file, no external dependencies)
If you are using LGPL Qt, you must read this:
https://www.qt.io/faq/3.7.-what-are-my-obligations-when-using-qt-under-the-lgpl
Yo can use Qt and static linking, but "The user of your application has to be able to re-link your application against a different or modified version of the Qt library"
You can use an application template like this, very useful for LGPL Qt:
https://marketplace.qt.io/products/qt-lgpl-app-template
I'm really new to Qt creator and actually I think my very short experience with it didn't go so well.
Anyways, my question is:
I used to write C++ programs using Code::Blocks IDE, now I'm trying to make some simple GUI to my program. So that's really why I used Qt creator in the first place.
I have multiple C++ files (.cpp) and (.h) how can I use them into Qt and integrate both "Qt user interface" with my C++ files.
I tried to google about it but got nothing. If anyone can help me how to start, or point out some good tutorial.
You mostly need to write a Qt project file (with some .pro extension) for Qmake (perhaps using qmake -project), then use qmake to generate a Makefile, then use GNU make to build your program.
Qtcreator is an IDE which might help you, but if you want to use some other editor or IDE, you can run the commands mentioned above appropriately. Actually, once you have generated once your Makefile, it might be auto-regenerated appropriately when needed. So configuring your IDE to use make is probably enough.
I try to use Xcode (v.7.3.1) for my C++ project (build system - make), but the experience is quite poor (and it was always like that since old versions like v4 when I started using it) - code completion doesn't work, color syntaxing works oddly (no coloring sometimes, or partially colored code), no "jump-to-definition" functionality, can't switch b/w header/source files with shortcuts. Basically, it's just a text editor where I have to use "Find" and Cmd+Shift+O all the time.
Is this intentional and Xcode will never get any proper support for C++ projects with external build system (make) or am I misconfiguring my project? How can I re-index files in the project? How can I make code completion work?
Thanks,
I believe there is a way to use Xcode with makefiles by adding an external build target, file->new->target->External Build System.
This is an older tutorial but the steps may be worth looking through: http://web.ist.utl.pt/jose.alberto.coelho/mac/MakefilesXcode.pdf
I've never had a problem with the syntax highlighting, but I remember the refactoring support being limited for C++ in some ways.
So, I ended up using this workaround: even though, I use external build system, I create Console Application project in Xcode and choose C++ language in settings. Then, I simply add my source files to the project (just drag folders from the Finder window) and then manually create project targets of type External Build System as I need. I don't use default target and don't use generated main.cpp file at all.
My files get indexed with no problems. I'm also able to debug code as I used to.
I still think Xcode developers should review indexing process for the projects with external build system...
Thanks for all the insights though!
I've downloaded the midiIO library and in the readme it says:
edit the file Makefile.library and set the OSTYPE and OSSUBTYPE to match your hardware/os setup.
type "make library" to compile the library. It will be created as lib/libmidiio.a in unix.
edit the file Makefile.examples and set the OSTYPE and OSSUBTYPE to match your hardware/os setup.
Also, if you are using ALSA, then uncomment out the POSTFLAG to use the alsa library (-lasound).
type "make examples" to compile the example programs in the examples directory. The example programs will be place in the bin directory.
1 + 3 are fine but 2 + 4 are over my head. I've worked in a unix environment before and have used gcc with flags but I need to get this done in Windows. I typically use Visual Studio but don't know how to achieve this with that.. I've downloaded Dev-C++ if that's any use but I don't know what to do with the makefiles?
Ignore the makefiles and set up a fresh project in Visual C++. Make your target a static library (which will be a .lib file in Win32, not a .a file as in unix as you probably know). It is unlikely that the project will build out of the box, so you might have to deal with some compilation errors relating to unix-specific symbols. I took a quick look at the source code, and it looks fairly well-written, so I don't think you should have many problems building it directly in Windows.
Alternately, you could build the source using the real make tool in cygwin, but this means that you would need to distribute the cygwin library with your final product. This may or may not be more trouble than it's worth, especially if you are already using VC++ for the rest of your project's code.
I am trying to open an existing C++ open-source library in Xcode to publish it with my own modification/additions. The library is Tesseract-OCR, which does not include a .xcodeproj file.
Since Xcode can function as an IDE, is it possible to open a bunch of files as a single project in Xcode? Is there an easy way to produce an Xcode project?
There are several ways you could do it, depending on the level of IDE integration you want. There's no direct way of importing a Makefile-based project into Xcode. You can create a project that builds via the Makefile, but you wouldn't get many of the benefits of using an IDE, since the editor features such as word completion rely on Xcode being able to parse the files in the project. You will be able to use the debugger though. To do this, create a new project and add a custom target with a script build phase that just calls down to Makefile.
If however the project you're building compiles very easily, ie without requiring a lot of macros to be set up, include paths, etc, then it may be simple to just create an empty project and merely add all source files to it. I've used this method extensively for building boost libraries. If this is a configure && make type project then you will probably have to run the configure step first, and ensure any top level config.h files are included in the project.
If the project has a complex makefile then it is likely to be an involved task to create a useful Xcode project
I realise you asked explicitly for Xcode, but in case you were actually trying to solve the problem of "I have existing C++ code which builds and runs fine from the command line, and I'd like to code and debug it in an IDE, what should I do?" my firm recommendation would be to avoid Xcode and go for Eclipse.
The reason is that as far as I can tell, Xcode has no way of ingesting the command line build environment and effectively requires you to recreate the make process inside Xcode from scratch. Fine for tiny projects, but anything with more than a few source files and it quickly becomes painful. Whereas in Eclipse everything is built around Makefiles. So in my case I got to the "step through code with working code completion" in Eclipse a lot quicker vs. never in Xcode. This of course could be because I'm an Xcode noob, but my 2c.
To create an Xcode project from an existing cmake project, you can run cmake -G Xcode. It produces some folders and files apart from the project file, so it might be better to create a folder for it first. For example:
mkdir -p build/xcode
cd build/xcode
cmake -G Xcode ../..
Xcode is a useable IDE for library creation.
Of course a good first step is to see if the one source code will build on its own with configure scripts that are included.
If not, it becomes a question of how many libraries you need to link in.
There are resources online (or at least there used to be) for using Xcode (or perhaps it's forerunner Product builder) for porting Unix projects to Mac.
Good tutorial at: http://www.macresearch.org/tutorial-introducing-xcode-30-organizer
Another good reference is Darwin Ports.
As for doing this on your own. You can build c++ based libraries in XCode. People do that every day. You can even use one of the Xcode templates to get you started.
However, library dev requires more experience with Xcode then say a simple Cocoa "Hello World" app.
The remaining questions will be assuring that the source code's dependencies are already built into the Mac's SDK. (Don't hold your breath for linking to MFC)
It's a general question... So it's a general answer.
In Xcode8,there is "Xcode->file->add files to...",then choose your files.If you want to add several files at a time,press "Cmd" when you are choosing.