how many dynamic features are there in QT(Not in QML)? - c++

We know that Qt has a plugin architecture that makes it possible to load code into an application without recompiling or relinking.
We also can integrate javascript into Qt using QScriptEngine.
I am wondering if there are any other dynamic features in Qt, which can add new features/functions to our application, without recompling or relinking.

Maybe too many (that's why your post is downvoted)
For example, you can get a python shell in your code without changing almost anything via the PythonQt library
You can get Lua too!

Related

Link c++ object during runtime?

I'm trying to write my first game in c++, and I want it to dynamically load everything from files. This includes the enemies, and I was wondering if there was a way to dynamically include their code at runtime, instead of linking the on compile, so that the levels are easily interchangeable. Lua might be an option but I have no clue where to start, and dll seems to be Windows-only (and I wouldn't know where to start there anyway). Can anyone help with this?
tl;dr I want to link in code to my c++ game at runtime.
For the Lua approach you first need to choose the version first. Right now there is the major version 5.1 and 5.2. My previous work was using 5.1 and for my new project I decided to update to 5.2, however I found that my favorite script wrapping tool (SWIG) does not work with 5.2. Just something to decide at the beginning, because you do not want to get a version working and then have to change it.
Lua comes with makefile build environment. My first experience of trying to build on Windows was a bit of a nightmare, did not appear to just run out-of-the-box, so I opted to create my own Visual Studio project at the time, and just include all the .C files in the project. There are two files which need to selectively included/excluded depending on how you intend to compile: lua.c and luac.c. If you are planning to embed Lua in your app, then exclude both of these files; they both contain a main() function and are designed to build console apps. Include all the rest of the C files in your project.
You should be able to compile easy from this point.
When you include the headers of Lua, keep in mind that the functions are C functions so if you are including them from C++ you need to wrap the file inclusion inside of: extern "C" {} - example: C++ Lua 5.1 Issue
Wrapping your interfaces in another topic and there are lots of resources available. My favorite is SWIG but there are lots of options, including hand coding the conversion of your C/C++ -> LUA -> C/C++ code. Would recommend just focusing on getting the first part working first, get the interpreter embedded so that you can run a "hello, world!" script from Lua inside your app.
So going by your requirement of crossplatform use and dynamic linking, what you're probably looking for is an environment like QT which has QLibrary: https://stackoverflow.com/a/9675063/453673
But https://softwareengineering.stackexchange.com/questions/88685/why-arent-more-desktop-apps-written-with-qt
MingW is the open-source equivalent for Visual C++, so it can help you writing code for Windows (though if I had a choice, I'd directly use Visual C++). The way dll's are loaded in Windows is somewhat similar to the way they're loaded in Linux, so you'll be able to write code with #ifdef's to do conditional compilation. I've written one such program a couple of years back.
To load a shared library(always with .so as suffix) under Linux, you could use dlopen(), dlsym() and dlclose()

Packaging a modified Qt class

Heads up, this is going to be confusing:
I customized 9 files from Qt5.2: qquicktextdocument.cpp qquicktextdocument.h qquicktextedit.cpp qquicktextedit_p.h qquicktextedit_p_p.h qquicktextnode.cpp qquicktextnodeengine.cpp qquicktextnodeengine_p.h qquicktextnode_p.h
Each file is simply prefixed with a letter and still inside /qtdeclarative/src/quick/items/. I am 100% happy with the modifications I made being put under GPL etc. I somewhat want my end application (discussed below) to be Apache or MIT, but, I'm flexible.
My modifications work fine. When I modify a few additional files I am able to compile them along with the rest of Qt (at the same time, using the same make command). But these modifications are going into another Qt application that I am making which I want other people to be able to use, and requiring general consumers to have a custom compiled version of Qt would be obviously absurd.
I want to package/compile/do something, that will enable me to include the modifications in my final project as a shared library, or something.
As a web developer writing C++ and Qt, I am very confused about linking shared libraries, header files, etc.
To recap, I modified Qt 5.2 and made a custom compilation of it for an application I am building, and I want people to be able to run that application without having to have a custom compilation of Qt. I need a way to decouple my Qt modifications from Qt.
I realize this might be a big topic, I'm not expecting a step by step guide, just some general guidance. So far I have tried compiling my modified files as a library, then including that library in my actual project, but I am getting undefined references and missing files all over the place. (I don't know if I did anything right)
I am also currently looking at subclassing the classes I want but I'm unsure about this. It might require copy pasting some code, which could have licensing issues?
end goal: be able to have a wavy underline (in qml) for incorrectly spelt words.
Thank You.
My 5 cents.
If your changes can be useful (in general) to other people you can try to push them to upstream via codereview.
If you want your application to run only in windows everything become obvious: in windows it is normal to provide your application with shared libraries (to avoid DLL HELL). Btw, have you heard about static linking?
Qt has some plugin mechanism. You can compile your code into shared object (dynamic library) and install it with your application. For example, QML FolderListModel do this. You can look at code in $qt5_src/qtdeclarative/src/imports/folderlistmodel.

AS3 to C++ conversion – possible?

I built an iPad app in actionscript. A potential partner wants to pull my app into their app. They built their app natively using XCode. From what I understand, if my app had been built natively, I could simply export the code as a static library (.a file) for use by their app. Alas, I built mine in actionscript. So...
Is there a way to convert ActionScript 3 to C++?
Is one possible solution to do this conversion via AS3 to Haxe to C++?
Am I simply SOL and need to rebuild the game using XCode?
Thanks in advance.
Jason
You might consider the Tamarin project or Tamarin redux.
http://www-archive.mozilla.org/projects/tamarin/
It can be compiled in XCode as well. However, if your application is heavily depended on Flash runtime you have to implement all classes by yourself, because AVM contains only the basic AS3 classes.

C++ Reads/Writes XML without CLR

I know this is a very stupid question and I'm very new to C++.
I'm developing Starcraft AI, it is DLL file. I'm trying to use XML to gather some data to the bot, however whenever I build the DLL with /clr option. The bot doesn't load properly. So, my question is what is CLR and is there a way to read/write XML without using /clr build option.
Thanks so much.
The /clr compiler option enables the
use of Managed Extensions for C++ and
creates an output file that will
require the .NET Framework common
language runtime at run time.
(from MSDN)
Starcraft is probably not developed under CLR (.NET Framework runtime).
I've used the free tinyxml library from C++ code - it was quick to get running and reasonably efficient. Well, about as efficient as it's possible for XML to be, anyway.
Starcraft probably won't run .NET binaries. You would have to either write your own XML parser, which probably isn't for you seeing as you are new to C++, or find a C++ library that can do it for you.
Example of one:
http://sourceforge.net/projects/tinyxml/

What API/SDK to use for this Windows Application?

I'm going to create a utility with GUI that will run on Windows operating systems.
It should require minimum (or zero!) amount of additional libraries, files or DLLs to run because it will be executed from an installer. Because of this, i don't want to use .NET for it will require user to install .NET Framework. I know today, most of Windows installed system come with .NET Framework but in my case i cannot be sure.
The utility will...
send some data to a web site and
parse the returning data,
collect some hardware info, like MAC address,
CPU type and make, hard-disk serial
number
I suppose native Win32 API could be used for all of those above, but instead of hassling with Win32, i'd prefer using a more developer friendly API, or SDK.
Thanks in advance.
Win32 API is the only way, and of course there are standard API - for sending data over the internet, you could use WinInet.lib/dll, to obtain information about the MAC, you could use the GetAdaptersInfo by using Iphlpapi.lib/dll,(here's a link on how to use it) for the Hard disk serial number you could use GetVolumeInformation by using kernel32.lib/dll. For the CPU Id, you might look into GetSystemInfomation
Edit: There's a C++ code, but you can easily derive a wrapper from this site Unfortunately, with WinAPI is not easy, no such thing as RAD with WinAPI but what you gain out of it is lightweight code instead of relying on SDK's, frameworks and dragging buggy dll's around with your application.
Hope this helps,
Best regards,
Tom.
You can statically link most C++ GUI libraries - even MFC. Personally, I recommend WTL, wihich is very light and header-only.
If what you want is minimum dependency with external files or DLLs you could statically compile all the required DLLs with the tool exe. Then you could use something like Visual C++ to develop such tool.
WTL is perfect for this sort of application and I am surprised more people aren't recommending it. You can also statically link with the CRT and hey presto - no dependencies and a very small EXE.
Delphi (now by Embarcadero) would do the job, creating a .exe file with no dependencies, and it is much easier to work with than the raw Win32 API.
If you don't like Object Pascal, you could try C++ Builder instead.
For the GUI you can either build your application with MFC (statically linked) or use a HTML based dialog that you can interact with using COM. (It is even possible to interact with javascript present in the page displayed by the dialog).
For the specific requirement that you do have, I feel Win32 API is the only way out.
Use MFC and statically link to it. No runtime dependancies need to be installed.