First of, I am very new to programming, but took an interest in it. I have successfully built a C++ Console program for Windows which is a simple Database program, which can edit / delete / input entries.
I am less and less relying on Windows for day to day stuff. I had an old HP Netbook which was impossible to use with Windows, but I put in a Linux Distro and works like a charm.
As I sometimes do use Windows, as well as having built the program to use in Windows, I am wondering if the same code can be used to compile a Linux program? I could use WINE to run it but would prefer running something specific to Linux. Is this possible with the same code or would I have to make another Linux version of it?
I would assume that since you are new to programming, that you did not make the extraordinary effort to make your code portable across platforms. That takes a significant skill set, especially if you are accessing external resources such as a database. So the answer is you will probably have to re-write for Linux, and specifically the database interface.
I guess that you want your C++ code to be compilable both on Linux and on Windows. You'll need operating-system specific compilers for that (a different one on Linux and on Windows).
I am wondering if the same code can be used to compile a Linux program?
The program to compile your C++ code is called a compiler. On Linux you will use GCC as the g++ command (which you could even customize with MELT, but that is not for newbies), or Clang/LLVM as the clang++ command. You'll use a builder like make (see here for why, and this example). Be sure to install a recent version (GCC 4.9 or Clang 3.5 at least in start of 2015) to get good C++11 support. Focus on learning C++11 (or C++14) not some earlier variant (so use a C++11 compiler).
I don't know Windows so I cannot recommend any good C++ compiler for it (but I heard of MinGW, CygWin and of Microsoft Visual C++; look also into recent Clang...).
You might be interested in cross-platform C++ framework libraries like Qt or POCO (and perhaps also Sqlite for database related stuff). They will help you to code some C++ usable on both systems (after recompilation).
BTW, you can always encapsulate your system specific code with preprocessor directives à la #if LINUX ;take care of putting all the OS specific (or OS related) code in a few source files.
It could happen (and I wish that for you) that you get fond & happy of Linux and will, in a few months, prefer to code for Linux only (you'll then install Linux on all your machines). BTW, study the source code of existing free software you like and use on Linux. That will teach you a lot.
The advices I gave here and here are still relevant today when coding on Linux. Read also something about porting & portability, and Advanced Linux Programming.
Related
I use the Dev-Cpp program with the MinGW compiler that allows you to compile C / C ++ code to obtain a Windows launcher, but is there a compiler for Windows that allows you to create executables for Linux?
You can install Windows Subsystem for Linux, or set up a VM and do it that way.
Or as #user4581301 mentioned, use a cross-compiler.
http://metamod-p.sourceforge.net/cross-compiling.on.windows.for.linux.html
Ignoring the fact that Dev-C++ has been obsolete for nearly a decade (I may have an unpopular opinion however that you should use whatever tools you can to learn whatever you can, even if that means using 'obsolete software' [as long as it's purely for learning and not production use])...
You have a couple options, one of which has been mentioned by somebody. 1.) Use a cross-compiler, and 2.) (which I personally would recommend, if it is viable for your particular needs) simply compile on actual Linux.
To do this, you just need a working distribution of Linux with a development environment. You can use a virtual machine, Windows Subsystem for Linux (WSL), or a physical machine with Linux running on it.
From there, if you want the code to compile for multiple operating systems, you'll have to make sure your libraries and frameworks and other OS-specific code (e.g., filesystem paths, system calls) are properly handled, or just use cross-platform libraries. If you're dealing with standard C/C++, then this won't be of any concern.
Since Dev-C++ uses MinGW (the Windows port of GCC), then the actual compilation process should be the same, although on Linux IDEs are not commonly used, so you may have to get your hands dirty with shell commands, but that's not too hard once you get started. Good luck!
For a few years I was writing programs in Visual Studio for Windows and with GCC (Code Blocks) for Linux. Most of my libs compiled seamlessly as they worked both in Windows and Linux. However at the moment I am a bit confused, as I have to create an app using Cygwin. I don't really understand if I am still in UNIX/Linux environment, just running app on Windows by some "emulation", or I am rather on Windows just having access to some Linux/Unix functionality. From what I understood from the FAQ's and documentation it looks like I just should behave like in Linux environment.
All explanations I found in internet usually are very general and don't explain the detailed differences from programmers viewpoint.
Short question: Can I just write programs like I did for Linux without any major changes when using Cygwin?
Maybe.
A lot of code written for Linux will compile in Cygwin with very few problems, which can mainly be fixed by messing with preprocessor definitions.
However, any code written for linux which:
Uses a Linux driver
Directly accesses the kernel
Relies on any code which does either of these two things (and doesn't have a Windows counterpart)
will quite definitely not work, regardless of how much you modify the code.
Much as it tries to, Cygwin cannot fully emulate (yes it is an emulator, of sorts) everything a POSIX system can normally do. Cygwin is not windows, just a conversion layer from its own machine language.
For more information, read cygwin's wikia
Can I just write programs like I did for Linux without any major
changes when using Cygwin?
The platforms are not identical, so you can not realistically expect to write the program in Linux, and then POOF expect it to build and work under Cygwin. But if you don't use things not available under Windows, then you won't need major changes. And you can write non-trivial programs, which will build and work on both, perhaps needing a few #ifdefs in places.
From your question I take it you want to work on Linux, but write programs for running under Cygwin. In that case you must also build and test it in the Cygwin environment all the time, so:
Use version control, commit often. I recommend a DVCS like git or mercurial which have separate commit and push, it will allow you to do commits more freely.
Whenever you commit/push, do checkout/pull and build on the Cygwin host. You can do this manually or automatically (by simple custom script polling the version control, or by Jenkins or something).
When ever your code stops building or working under Cygwin, fix it before continuing with new code.
If Cygwin is not absolute requirement, then I would look into using Qt SDK. It can be used for non-Qt projects too, the MinGW toolchain on Windows is very similar to gcc on Linux. And if you're willing to use Qt, then it has all sorts of platform-independent features for things you might want to do, such as discover locations of standard directories for saving files, use threads, print things, have GUI...
How could I write a program which runs on both Windows 7, Mac OS X (and maybe linux too)?
I heard Qt are a great framework to build cross-platform GUIs, but I think every program version need a recompile, isn't that right? And should I compile the win version under windows, the mac version under mac os x, the linux version under linux and so on?
I'm getting ideas and/or suggestions
The underlying binary format is different on each platform, so unless you're using a virtual machine (like Java or Flash does) you will have to recompile your program on each platform.
Some compilers (like GCC) allow cross-compiling, but it is not trivial to set up. Probably the easiest system to cross-compile on is Linux (there are several open source projects that have cross compilation set up from Linux to Windows).
In case of a GUI application, it depends on the language -- if you're stuck with C++, Qt or wxWindows might be a reasonable choice providing an abstraction layer over the native windowing system.
If you can go with Java, it makes life simpler, however the windowing system is Java's and not native.
Another language to think about is FreePascal w/ Lazarus -- it has a pretty good GUI designer that compiles to the native windowing system on every platform (WinAPI on Windows, Cocoa on OSX and GTK on Linux).
Not sure if C++ is a must, but Adobe Air is a great cross platform development environment for desktop, and its growing for mobile development as well. If you need an example of a major application using Adobe Air to deploy to multiple desktop OSes, just check out tweetdeck http://www.tweetdeck.com/
I'd highly suggest also looking into Flex and Flash Builder if you go that route.
There are two separate issues I would highlight when writing cross-platform programs -- how to make your code portable, and how to arrange for it to be built on the various different platforms.
As far as the building side of things goes, I would look into a cross-platform build system like CMake (http://www.cmake.org). You essentially write a script and CMake will generate the appropriate project file/makefile for a specific platform. You then build your program on each platform as you would normally. For example, on Windows, you might use CMake to generate a Visual C++ project for you, and then use Visual C++ to actually build your executable. On Linux, you might use CMake to generate a makefile, and then build the executable using g++.
The other aspect is how to make your code portable -- the key is to write C++ standard-compliant code and make use of libraries that are themselves portable across the platforms you're interested in. You can (and may sometimes need to) write platform-specific code for each of the different platforms -- if you do, you should hide it behind a portable interface and have the rest of the code use that.
Yes, you need to compile for each version when using C++.
The only thing that prevents you from compiling a program, for example, for Windows on Mac is to get a tool for doing that. It is possible, but the problem is finding the toolset.
Also you can use a virtual machine for running diferent OSs and compiling code for all platforms on the same machine.
Java runs on Windows, OS X and Linux
I am trying to figure out which C/C++ compiler to use. I found this list of C/C++ compilers at Wikipedia:
http://en.wikipedia.org/wiki/List_of_compilers#C.2FC.2B.2B_compilers
I am fairly certain that I want to go with an open source compiler. I feel that if it is open source then it will be a more complete compiler since many programmer perspectives are used to make it better. Please tell me if you disagree.
I should mention that I plan on learning C/C++ mainly to program 2D/3D game applications that will be compatible with Windows, Linux, MAC and iPhone operating systems. I am currently using Windows Vista x64 OS.
First of all, IMHO as a beginner your development environment (IDE) matters a lot more than the compiler.
I think that people place too much emphasis on compiler choice early on. While it is not Java, C++ is meant to be portable.
If the program you're writing only works with specific compilers, you're probably doing the wrong thing or can work a little on making it more portable.
If you get to a point where compiler choice makes a significant performance impact for you, then you've already perfected everything else in your program and you're in a good state and you are also quite advanced in your abilities. We used to teach the differences between compilers at fairly advanced stages in the CS curriculum.
If you use a UNIX based machine (Linux, Mac, actual Linux), then pretty much GNU (g++) is the way to go and is fairly much standard. If it's good enough to compile your OS, it's probably good enough for you. On a mac you can use XCode as your IDE, and it interfaces well with g++. On Linux some people prefer command line tools, though you might like the Eclipse C++ support, it is much better today than it was 3-4 years ago.
Things on Windows are trickier. If you can afford it, have access to, or are eligible for one of the free editions (e.g., via a school), I think the Microsoft Visual C++ Environments (or whatever they are called now) are pretty good for learning and they are used in production. I think there's actually a lightweight visual studio now with an emphasis on C++ that could be a good start. If you don't, you can probably find a distribution of Eclipse that is specific for C++ and includes an implementation of the GNU compilers.
Use gcc and g++ while you're still learning these languages, a big enough task for now. If you need a specialized compiler down the road, you'll want to have much deeper understanding of the language and your problem domain to properly evaluate candidates.
I feel that if it is open source then it will be a more complete compiler since many programmer perspectives are used to make it better.
That's not necessarily true. You could also say that if you use Microsoft's compiler, it will be optimal for Windows, since Microsoft knows best how to optimize a compiler for Windows.
Microsoft has Visual C++ Express Edition which is free and ofcourse includes a nice IDE that's very well suited for Windows development.
But if you're interested in making portable software, look at GCC, which is the default compiler on Linux and which is also available on the Mac. (The iPhone works totally different and requires special tools that only run on Mac OS X). You can get GCC for Windows with Cygwin or MinGW.
Get the Visual Studio Express (easier and quicker IMO, to setup) and learn with it; when you think you know enough about C++ and how "things" work, you could start using something like QT or GCC (with cygwin) and learn to port to different platforms.
For windows u can use CodeBlocks I believe it uses gcc and its pretty user friendly
I strongly suggest going with MinGW.
It is:
Open-source
Available on all major platforms
Comes with standard Win32 headers and libraries
The key to writing portable C++ code is:
Use a cross-platform version control system (subversion is a great choice), because this makes it easier to
Compile and test your code on other platforms early and often
I have the source code for some very simple command line programs. I was considering the option of compiling them on a Linux machine (they were deveoped here) so they can be used on Windows. If I am not wrong this is called Cross-compiling. I have never tried it, but reading yesterday some information, it seems to be kind of complicated or not successful. I would like to hear about your opinions, and how could I port a simple "hello world" program, which compiles on Linux with g++.
Thanks
Look into mingw, a suite of tools for building Win32 applications in Linux. If the programs don't depend on any Linux-specific functionality not supported by mingw, you should be fine.
Note that cross-compilation is not the same thing as cross-platform. With cross compilation, you compile the code to a Windows executable on the Linux box, then transfer the executable to a Windows box. With cross-platform, you transfer the source code to the Windows box and compile to a Windows executable using a Windows compiler.
The former is quite difficult (but not impossible), the latter is very easy, using a compiler such as MinGW, a others have mentioned.
I cross-compile on a daily basis. But I don't set up cross-compilers on a daily basis. It can be tricky, but it's certainly possible.
As long as you use standard C++ your code will be cross-platform. You can also use cross-platform libraries like STL, boost, Poco, Qt, etc...
Only when you start to use platform specific code you lose portability. For example including <windows.h> will make your code only compilable on Windows. (There are techniques around this like the #ifdef macro. This enables certain code portions only on one platform.)
So a simple hello world program should work on Linux, Mac, Windows or any other platform. You don't need anything special for this.
Note:
Some may mention Cygwin or mingw32. I'll briefly explain what they are:
Cygwin allows you to compile Linux applications using gcc/g++ on a Windows machine.
Mingw32 allows you to compile Windows applications using gcc/g++ on a Windows machine.
Edit:
If you want to setup a system for cross-compilation, then I recommend that you have a look at cmake.
Yes. We are currently compiling a 250 kloc app, running Qt with daily builds. It's working prefectly everyday, although I've to admit it is not distributed outside the company, but only used internal. For official releases, Visual Studio is prefered.
Compiled using mingw standard packages on Debian.