With native c++, I mean, not managed c++, not cli, not any special things from microsoft, I can:
1) get high performance
2) use existing c++ code library and engine
3) write cross platform code (for example, for ios and android)
it needn't be fully native c++, I can use managed code to do the ui things, like object-c in ios and java in android, but beside interface, can I use native c++ code?
I suggest you have a look at the presentation here: Using the Windows Runtime from C++ and especially at the comments from Herb Sutter. I quote:
Please answer this question: If I decide to write C++ GUI application
in Metro style am I forced to use all these proprietary ref, sealed,
^, Platform::String^ extensions for GUI components or not?
#Tomas: No, you are not forced to use them. We are providing two
supported ways:
1) These language extensions (C++/CX).
2) A C++ template library (WRL), see
Windows Kits\8.0\Include\winrt\wrl as Yannick mentioned. WRL is a C++
library-based solution sort of along the lines of ATL, which offers
what I think you're looking for -- template wrapper/convenience
classes and explicit smart pointers and such.
Yes you absolutely can, real native C++ is fully supported.
You do however mostly have to use the new WinRT libraries to do an user interface or system calls and although they are native code and fully callable from C++ directly the interface to them makes it very painful indeed to do so, as everything is a reference counted COM object and in addition it's not so easy to create instances of them as just calling "new" so you have to write a lot of ugly code to do so.
As the earlier answer said, microsoft provide two ways to help with this. One is via language extensions to c++ and the other is a c++ template library. Personally I consider both to be rather ugly for doing something as simple as calling an API but that's just me :)
But to answer your question, it's completely possible to write your application in real native c++. You won't need to use managed code at all for anything. But you'll probably want to use either the language extensions or the template library to make calling the API more easy.
Personally I'm hoping someone writes a wrapper for WinRT that exposes the most necessary functionality as a more usable c++ native library and then everyone can just use that from c++ instead...
Related
Considering Simon Mourier's answer to this question:
Processing Microsoft Office Outlook 2003/2007 email messages…
I plan to use the PST File Format SDK which is written in C++.
I would take this opportunity to learn more about C++ and to renew with it, since it's been quite 15 years since the last time I used it. I have already downloaded and configured Boost 1.45 which is required to work with pstsdk.
Now, I'm currently writing a Windows Forms application using CLR C++ and plan to use the pstsdk to read from PST files.
Does it matter in any way that I'm using both CLR C++ and pure C++ altogether?
Shall I consider using it a different way, or is this okay?
If you want to use a .NET (Windows Forms, or maybe even the newer WPF) user interface, the simplest approach is to build an object model in C++/CLI, implemented in terms of the native code but having a .NET interface.
Then write the UI in C# and call the C++/CLI object model (which differs from using the .NET base class library in only one way -- you have to add a reference to the C++/CLI assembly... but the C++/CLI compiler will create all the metadata that C# uses).
You can mix managed and unmanaged code, but it will be a pain to marshal everything except the built-in types across the boundaries. It's much easier to stay with more powerful unmanaged C++. You could use CodeGear C++ Builder for example (or QT). The problem with CodeGear is compiler isn't that great, so you won't be able to compile everything from Boost, but you might not need that.
C++/CLI is intended to interop with unmanaged C++- that's pretty much it's entire purpose. However, I feel that it's probably easier to write in C# if you need .NET for, say, WPF, which is an excellent technology, and just use C++/CLI for interop.
I'm just starting my first C++ project. I'm using Visual Studio 2008. It's a single-form Windows application that accesses a couple of databases and initiates a WebSphere MQ transaction. I basically understand the differences among ATL, MFC, Win32 (I'm a little hazy on that one actually) and CLR, but I'm at a loss as to how I should choose.
Is one or more of these just there for backward-compatibility?
Is CLR a bad idea?
Any suggestions appreciated.
Edit:
I've chosen C++ for this project for reasons I didn't go into in the post, which are not entirely technical. So, assuming C++ is the only/best option, which should I choose?
It depends on your needs.
Using the CLR will provide you with the most expressive set of libraries (the entire .NET framework), at the cost of restricting your executable to requiring the .NET framework to be installed at runtime, as well as limiting you to the Windows platform (however, all 4 listed technologies are windows only, so the platform limitation is probably the least troublesome).
However, CLR requires you to use the C++/CLI extensions to the C++ language, so you'll, in essense, need to learn some extra language features in order to use this. Doing so gives you many "extras," such as access to the .net libraries, full garbage collection, etc.
ATL & MFC are somewhat trickier to decide between. I'd refer you to MSDN's page for choosing in order to decide between them. The nice thing about ATL/MFC is that you don't need the .NET framework, only the VC/MFC runtimes to be installed for deployment.
Using Win32 directly provides the smallest executables, with the fewest dependencies, but is more work to write. You have the least amount of helper libraries, so you're writing more of the code.
Win32 is the raw, bare-metal way of doing it. It's tedious, difficult to use, and has a lot of small details you need to remember otherwise things will fail in relatively mysterious ways.
MFC builds upon Win32 to provide you an object-oriented way of building your application. It's not a replacement for Win32, but rather an enhancement - it does a lot of the hard work for you.
System.Windows.Forms (which is what I assume you meant by CLR) is completely different but has large similarities to MFC from its basic structure. It's by far the easiest to use but requires the .NET framework, which may or may not be a hindrance in your case.
My recommendation: If you need to avoid .NET, then use MFC, otherwise use .NET (in fact, in that case, I'd use C# as it's much easier to work with).
As far as C++ goes, I would use WTL. It's lightweght and you will have few (if any) dependencies, making it easy to ship and install. I find it very satisfying when my app consists of a single EXE that will run on most versions of Windows, but this may not be a concern to you.
If you choose to go .NET instead, then C# is almost certainly the way to go.
More in WTL here:
http://www.codeproject.com/KB/wtl/wtl4mfc1.aspx
I would be very curious as to why you would do this in C++ at all. Based on your brief description, C# sounds like a much more appropriate choice.
Just to elaborate a bit, look at the link you gave describing the C++ CLR. The top rated answer notes (accurately, in my opinion) that C++ is appropriate for "kernel, games, high-performance and server apps" - none of which seems to describe what you're doing.
MFC, ATL, etc are going to be supported in the sense that, yes you'll be able to compile your app on future versions of Visual Studio and run them on future versions of Windows. But they're not supported in the sense that there's not a lot of new development going on in the API or the language the same way there is in the CLR and C#.
There is nothing wrong with CLR. Like others here I'd suggest C# but as you have reasons for sticking with C++ then using the .NET framework is several thousand times easier than messing with ATL/MFC if you're not already familiar with them (IMO).
It may be worth mentioning that if you're using C++/CLR then you're not really using C++ at all. C++/CLR compiles to CIL just like C#. I've never used it myself but I believe its purpose is to allow you to compile legacy code and make it easily available to new .NET code rather than allow new code work with old C++ executables. There are other methods of calling native code from .NET which, perhaps, you should explore.
The modern (2021) answer to this question would appear to be to use C++/WinRT instead of C++/CLR (or C++/CLI or C++/CX... jeez Microsoft):
https://learn.microsoft.com/en-us/windows/uwp/cpp-and-winrt-apis/intro-to-using-cpp-with-winrt
C++/WinRT is an entirely standard modern C++17 language projection for Windows Runtime (WinRT) APIs, implemented as a header-file-based library, and designed to provide you with first-class access to the modern Windows API. With C++/WinRT, you can author and consume Windows Runtime APIs using any standards-compliant C++17 compiler.
...
C++/WinRT is Microsoft's recommended replacement for the C++/CX language projection
It's basically standard C++ but the UI is defined with XAML.
Still though, as with the other answers, it would appear that using C# is really microsoft's favorite approach. C++/WinRT really looks like it's almost C# anyways.
Are their any libraries which provide functionality similar to mono but for the c++ language? I know boost exists, but I like mono much more than boost.
I'm looking to do more than what's available in the base library set, like play sound more easily (crossplatform), GUI, load images, time, etc. I guess I am looking for what people might consider an engine or a large library.
Mono is a .NET implementation. Mono is NOT a library.
There is NO Mono for C++. At least, not yet.
I think you want a multi-platform framework, such as Qt
If you're wanting to work with Managed C++ a la .Net, then you would just use Mono. They have a page describing how to go about it. The only catch is that you have to compile on Windows, as there is not yet any flavor of GCC that outputs .Net CLI for C++.
To be honest, though, if you're going to use Mono, you might as well move into C#. It's a much cleaner language, IMO.
CLI is only able to host C++ compiled code on all supported platforms as long as the compiled code only contains CIL not native code.
for more detail visit
http://www.mono-project.com/CPlusPlus
I'm not sure about your precise requirements, but in terms of large multi-purpose packages: Qt has been mentioned by a few folks. wxWidgets (formerly wxWindows) is another option. GTK is multiplatform.
As you use the word "engine" (often a game-related term), you might be interested in SDL, which has been used by numerous games, professional and amateur alike. SFML is an option. ClanLib is another long-lived library I've heard of, though I'll admit to knowing little about it.
Try the STL collections...Has nothing to do with .NET, but they are a nice collection of collections (lol) and make C++ life easier.
It sounds like what you are really looking for is a C++ framework that offers the kinds of functionality found in the .NET/Mono framework. Qt is a popular choice.
On the topic of C++ interoperability, Mono has recently made some pretty big strides with CXXI.
(From this posting): The short story is that the new CXXI technology allows C#/.NET developers to:
Easily consume existing C++ classes from C# or any other .NET
language
Instantiate C++ objects from C#
Invoke C++ methods in C++ classes from C# code
Invoke C++ inline methods from C# code (provided your library is compiled with -fkeep-inline-functions or that you provide a surrogate
library)
Subclass C++ classes from C#
Override C++ methods with C# methods
Expose instances of C++ classes or mixed C++/C# classes to both C# code and C++ as if they were native code.
CXXI is the result of two summers of work from Google's Summer of Code towards improving the interoperability of Mono with the C++ language.
I need to build a C++ library to distribute among our customers. The library must be able to be accessed from a wide range of languages including VB6, C++, VB.net and C#.
I've being using ActiveX controls (ocx files) until now. But I wonder if there is a better kind of library (dll, etc.) that I can build. What do you recommend?
I'm limited to C++ as the library language, but you can mention other languages for reference to other developers.
P.S. Sorry if the question was already asked. I had some trouble finding a suitable title. Feel free to correct my English.
Edit: Seems like the best choice is either DLLs or OCX (i.e., COM), but I'm still having some doubts on which one will I choose. Which one is more suitable to modern languages (.NET for instance)? Which one would be easier to use from an end developer perspective?
Almost every language has a way of loading dynamic libraries and accessing exported C functions from them.
There is nothing preventing you from using C++ inside the dll but for maximum portability, export only C functions.
I have some more about this in this post.
If you're looking at supporting both VB6 and .NET, you're pretty much stuck with exposing interfaces via COM, but at least that'll get you out of having to create more than one wrapper based on the language/runtime system you're trying to interact with.
If there is any chance this will need to be ported to non windows platforms then a DLL / Shared library is your best choice as a COM object really isn't at all portable.
In addition you can call a DLL from almost any platform even if it requires you to write a wrapper of some kind. It's pretty easy to wrap a dll in a com object but if you make a native com object it's a lot harder to add a C style DLL API. Plus you might want to call it from java for example and it's much easier to write a JNI wrapper to call your DLL than get it working with COM in any kind of cross platform way.
Really it depends on what platforms you really need to call it from and how certain you can be that you won't get something out of the ordinary in future.
To be callable from all those languages your only real option is going to be COM, without having to write wrappers where required (which would defeat the point)
Plug-in systems in C++ are hard because the ABI is not properly defined, and each compiler (or version thereof) follows its own rules. However, COM on Windows shows that it's possible to create a minimal plug-in system that allows programmers with different compilers to create plug-ins for a host application using a simple interface.
Let's be practical, and leave the C++ standard, which is not very helpful in this respect, aside for a minute. If I want to write an app for Windows and Mac (and optionally Linux) that supports C++ plug-ins, and if I want to give plug-in authors a reasonably large choice of compilers (say less than 2 year old versions of Visual C++, GCC or Intel's C++ compiler), what features of C++ could I count on?
Of course, I assume that plug-ins would be written for a specific platform.
Off the top of my head, here are some C++ features I can think of, with what I think is the answer:
vtable layout, to use objects through abstract classes? (yes)
built-in types, pointers? (yes)
structs, unions? (yes)
exceptions? (no)
extern "C" functions? (yes)
stdcall non-extern "C" functions with built-in parameter types? (yes)
non-stdcall non-extern "C" functions with user-defined parameter types? (no)
I would appreciate any experience you have in that area that you could share. If you know of any moderately successful app that has a C++ plug-in system, that's cool too.
Carl
Dr Dobb's Journal has an article Building Your Own Plugin Framework: Part 1 which is pretty good reading on the subject. It is the start of a series of articles which covers the architecture, development, and deployment of a C/C++ cross-platform plugin framework.
You might also want to consider replacing the conventional plugin interface by a scripting interface. There are some very good bindings for several scripting languages in C/C++ that have already solved your problem. It might not be a bad idea to build on top of them. For example, have a look at Boost.Python.
Qt has a very nice system for plugins that I've used in the past. It uses Qt's meta-object system to overcome many of the problems typically found when trying to develop C++ plugins.
One example is how Q_DECLARE_INTERFACE works, to prevent you from using an incompatible plugin. Another is the build key, to make sure you load the correct plugin for your architecture, OS, compiler. If you don't use Qt's plugin system, these are things you will have to worry about and invent solutions for on your own. It's not necessarily rocket science, and I'm not saying you'd fail at it, but the guys at Trolltech are pretty smart and have spent a while thinking about it, and I'd rather use what they created than reinvent the wheel myself.
Another example is that RTTI typically doesn't work across DLL boundaries, but when using Qt, things like qobject_cast which rely on the meta-object system do work across DLL boundaries.
I think you are safe creating a plugin system based on:
Packaging of plugin functionality into library (.dll, .so, etc.)
Requiring that the plugin expose key C-language exports.
Requiring that the plugin implement (and return a pointer/reference to) an abstract C++ interface.
Probably the most successful C++ plugin system: good old Adobe Photoshop. And if not that, one of the virtual synth formats such as VSTi etc.
The book Imperfect C++ by Matthew Wilson has a nice info about this.
The advice in the seems to be: as long as you use the same (or equivelant) compiler, you can use C++, otherwise you're better of using C as an interface on top of your C++ code.
I have my own game engine that has a C++ plug-in system.
I have some code in header files so it gets put into the plugin's compilation unit.
Larger functions that live in the main engine are called via an exported C function (plugin calls MyObject_somefunction(MyObject *obj) which in the engine just calls obj->somefunction()). If calling a C function is ugly for your taste, then with some header trickery, when the header is included in the plugin, have the member function #defined to call the C function:
#if defined(IN_THE_PLUGIN)
void MyObject::somefunction() { MyObject_somefunction(this); }
#endif
Virtual functions either have to be pure or the code lives in the header file. If I'm not inheriting from a class and merely just instancing one, virtual function code can live in the engine, but then the class must export some C functions for creating and destroying the object that is called from the plugin.
Basically, the tricks that I have used, with the goal being to maintain total platform independence, just amount to C exports and header file tricks.
ACE has a cross platform plug-in architecture.
Check out:
ACE DLL
ACE DLL Manager
I would suggest checking out the book
The ACE Programmer's Guide
Firefox runs on XPCOM (http://www.mozilla.org/projects/xpcom/). It's inspired by Microsoft COM but it's multiplatform.