I have generated a c++ shared library and integrated it with a C++ console application which is called from php. I was trying this on my windows os and it works perfect. Now I have to transfer it into a linux web server. I know I have to compile the c++ console application in linux again to run it and may be generate the c++ shared library also. I am new to the linux os, how can I compile the c++ console application in linux server assigning all the additional library,include files,header files generated from the c++ shared library like we do in Visual Studio? Any link regarding this will be highly appreciated. As the shared library is from matlab I should also assign the matlab include files and libraries ewhile compiling the c++ console application.
I think you will have to get a Linux port of your matlab made library, which might involve getting matlab installed and working on Linux (and a little testing & debugging).
When your lib is ready, port your console application also (debugging et. all), open a terminal then:-
gcc -Wall console_app.c /path/to/your/libFromMatlab.a -o console_app
If your console app's source spans multiple files, you may want to consider using an IDE like code::blocks or use a makefile to simplfy your work.
Add your "libFromMatlab.so" (notice the .so vs the .a above) location to the library path (or copy it to where the others reside), then make sure your console_app has executable flag set.
NB:Developing on any platform other than the target platform without cross-compiling is equivalent to playing Russian roulette...only less lethal.
-----EDIT------I also came across this article and thought section 4 may be of some value.
Related
I would like to create a c++ application, which uses OpenCV, running on a server. To do this, I need to compile the c++ application on my server. But, how can I get my OpenCV libraries (and other libraries) on the server? Or is there another way to get my c++ application running on my sever? i.e. compiling on my own computer instead of on a server.
I hope you can help me! Thanks!
If the server is the same architecture (e.g. both intel x86 32 bit or both PowerPC) you should be able to compile on your own box and run it on the server.
Also, as noted by jlengrand below, you can set your computer up with a cross-compiler for just about any target architecture. That basically lets you type in a one-liner command to set up your compilation environment, then when you invoke g++ or whatever you're using, it will build for the architecutre the cross compiler is made for.
I don't know much about OpenCV, but as long as you have it set up to "statically link" the libraries then they should be part of your resulting executable. So, the executable would have all the libraries and it would be runnable on any computer with your computer's architecture.
Watch out for dynamic linking as it would mean the libraries themselves had to be present and locatable on the server when you run the executable though (dynamic linking means shared libraries, where they're not part of the executable and have to be provided separately. While dynamic linking is really better as things can be shared and updated, it is more complex for deployment).
I am looking to create a C++ library that can be used by both Linux and Windows clients. The OS specific functionality will be hooked up by the client by implementing the interfaces provided by the library.
Is this possible to achieve? Do I need to recompile the C++ project again in linux.
P.S: I am using CodeBlocks IDE
The short answer is no, you still need to compile your library for each targetted platform -- however, assuming your code is written such that it is cross-platform, you can set up your build to target both Windows and Linux environments with little fuss. I do this now using CMake to generate both Visual Studio projects for Windows environments and Makefiles for Linux environments.
I'm pretty confident that Linux will not accept a .dll :) And yes, you will need to recompile. Unless you run windows as a virtual machine under linux which sort of preempts the question.
It certainly cannot be the same binary file: shared objects ELF format on Linux, DLL "PE" format on Windows. And dynamic loading has different semantics on both systems. See Levine's linker and loader book for details.
You could, if done carefully, have the same source code giving the two different files (the DLL on Windows, the dynamic shared object on Linux).
But you probably would need some conditional compilation tricks like #ifdef WINDOWS etc...
You might use libraries providing you a common abstraction for such things. For instance, both GTK/Glib and Qt have some mechanism giving a common abstraction of dynamically linked (or dynamically loaded - ie dlopen-ed) libraries.
You probably want to read the Program Library Howto (at least for Linux).
How can i run a program which already has been built and compiled before on Qt IDE, so that i can take that program and run on any computer I want without recompiling it on that computer. I am a beginner so bare answering this question.:)
Thanks
There are a few parts to your problem.
1) You need to compile it for each architecture you want it to be used on.
2) Each architecture will have a set of Qt dynamic libraries associated with it too that need to be available.
3) Some architectures have an easy-to-deploy mechanism. EG, on a mac you can run "macdeployqt" to get the libraries into the application directory. For nokia phones (symbian, harmattan (N9), etc) QtCreator has a deploy step that will build a package for the phone and even include an icon.
4) For systems without such a feature, like linux and windows, you'll either need to distribute the binary and require the user to have Qt available or to package up a directory/zip containing the needed Qt libraries and distribute that.
It doesn't launch because it cannot find the dependencies. As you are on Windows, these libraries can be moved in the same directory as your application. To find which library is missing, use dependency walker
I am pretty sure these libraries are not found:
The Qt dynamic libraries (can be found on Qt bin directory, take the dll)
The C dynamic libraries used for compilation. If you are on creator and use default setting it will be mingw-xxx(can be found in the Qt installation directory, don t know exactly where)
Every Architect has a set of CPU Instructions.
so it's like when you hear a language that you don't understand. like when i speak Arabic To Someone who don't Understand The Language.
Every Architect Has a set of Processor Instructions, The Compiler only convert the code into instruction only understood by The Architecture that your CPU is.
That's Why Python and the most of High level languages Use Interpreter Instead of a Compiler.
But There are some cross compilers like MinGw that Support Cross compiling To Windows (.exe files)
Simply QT Have some libraries important to be in the working directory for your project.
I want to create a program that could work on any computer without the source code, How is that possible? and does it make any difference if I used OpenGL in the Program?
You cannot code a program in C++ that would work on any computer without giving your source code to be compiled.
For example, you could perhaps code in C++ a program, and compile it and build an executable which works on Windows x86-64, but that executable won't work on Linux (or MacOSX), and it won't work on ARM (e.g. Android phones) unless you consider using emulators
If you are developing your code with Visual C++ you may need to consider two options:
Make sure you link all libraries statically.
Install on the target computers along with your program Microsoft Visual C++ Redistributable Package corresponding to the Visual C++ version you use like the one at http://www.microsoft.com/download/en/details.aspx?id=5555. Some installer generating software will make it for you automatically.
Normally you would link your object file with some sort of a platform dependent loader. This loader loads your object and does all the stuff to start it from memory. Normally you can tell your compiler to link your object file and compile a blob. OpenGL is a powerful API and is usually distributed as a.dynamic linked library and is linked at runtime to your program. If I remember you just have to make sure the dll is where you want it and load the dll in your program from start.
Your C++ program is compiled and linked into an executable before it is run. You should be able to find that executable in a Debug or Release subfolder of the folder containing your project.
OpenGL, if you're not using GLUT or similar libraries, should just come with Windows and pose no additional problems. If you do use GLUT, it's enough to bundle the .dll file with your application.
In any case, the source code won't be necessary.
I want to create a program that could work on any computer without the source code, How is that possible? and does it make any difference if I used OpenGL in the Program?
By compiling and linking it into an executable. As long as you're not using some interpreted language (like Python, Ruby or such) you're presented with an executable inevitably. The biggest problem you may/will run into is dependencies on libraries. However those are linked into a binary as well. So what you're going to ship will be just a .exe; and some .dll maybe. Usually you'd wrap this in a installer package for deployment to the end user. Installers are created with something like the "NullSoft Installer System" (NSIS).
OpenGL itself is just a API, provided by a system library. So you don't ship OpenGL with your program, but expect the user to have it installed on the system (which will be the case if he installed the graphics drivers).
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I used to program in Windows with Microsoft Visual C++ and I need to make some of my portable programs (written in portable C++) to be cross-platform, or at least I can release a working version of my program for both Linux and Windows.
I am total newcomer in Linux application development (and rarely use the OS itself).
So, today, I installed Ubuntu 10.04 LTS (through Wubi) and equipped Code::Blocks with the g++ compiler as my main weapon. Then I compiled my very first Hello World linux program, and I confused about the output program.
I can run my program through the "Build and Run" menu option in Code::Blocks, but when I tried to launch the compiled application externally through a File Browser (in /media/MyNTFSPartition/MyProject/bin/Release; yes, I saved it in my NTFS partition), the program didn't show up.
Why? I ran out of idea.
I need to change my Windows and Microsoft Visual Studio mindset to Linux and Code::Blocks mindset.
So I came up with these questions:
How can I execute my compiled linux programs externally (outside IDE)?
In Windows, I simply run the generated executable (.exe) file
How can I distribute my linux application?
In Windows, I simply distribute the executable files with the corresponding DLL files (if any)
What is the equivalent of LIBs (static library) and DLLs (dynamic library) in linux and how to use them?
In Windows/Visual Studio, I simply add the required libraries to the Additional Dependencies in the Project Settings, and my program will automatically link with the required static library(-ies)/DLLs.
Is it possible to use the "binary form" of a C++ library (if provided) so that I wouldn't need to recompile the entire library source code?
In Windows, yes. Sometimes precompiled *.lib files are provided.
If I want to create a wxWidgets application in Linux, which package should I pick for Ubuntu? wxGTK or wxX11? Can I run wxGTK program under X11?
In Windows, I use wxMSW, Of course.
If question no. 4 is answered possible, are precompiled wxX11/wxGTK library exists out there? Haven't tried deep google search.
In Windows, there is a project called "wxPack" (http://wxpack.sourceforge.net/) that saves a lot of my time.
Sorry for asking many questions, but I am really confused on these linux development fundamentals.
Any kind of help would be appreciated =)
Thanks.
How can I execute my compiled linux
programs externally (outside IDE)? In
Windows, I simply run the generated
executable (.exe) file
On Linux you do the same. The only difference is that on Linux the current directory is by default not in PATH, so typically you do:
./myapp
If you add current dir to the path
PATH=".:$PATH"
then windows-like way
myapp
will do, but this is not recommended due to security risks, at least in shared environments (you don't want to run /tmp/ls left by somebody).
How can I distribute my linux application?
In Windows, I simply distribute the executable files with the corresponding DLL files (if any)
If you are serious about distributing, you should probably learn about .deb (Ubuntu, Debian) and .rpm (RedHat, CentOS, SUSE). Those are "packages" which make it easy for the user to install the application using distribution-specific way.
There are also a few installer projects which work similarly to windows installer generators, but I recommend studying the former path first.
What is the equivalent of LIBs (static library) and DLLs (dynamic library) in linux and how to use them?
.a (static) and .so (dynamic). You use them in more or less the same way as on Windows, of course using gcc-specific compilation options. I don't use Code::Blocks so I don't know how their dialogs look like, in the end it is about adding -llibrary to the linking options (guess what: on windows it is about adding /llibrary ;-))
Is it possible to use the "binary form" of a C++ library (if provided) so that I wouldn't need to recompile the entire library source code?
Yes. And plenty of libraries are already present in distributions.
Note also that if you use .deb's and .rpm's for distribution, you can say "my app needs such and such libraries installed" and they will be installed from the distribution archives. And this is recommended way, in general you should NOT distribute your copy of the libraries.
If I want to create a wxWidgets application in Linux, which package should I pick for Ubuntu? wxGTK or wxX11? Can I run wxGTK program under X11?
Try wxGTK first, dialogs may look better, gnome themes should be used etc.
If question no. 4 is answered possible, are precompiled wxX11/wxGTK library exists out there? Haven't tried deep google search.
Try
apt-cache search wx
(or spawn your Ubuntu Software Center and search for wx)
In short: you will find everything you need in distribution archives.
Navigate to the folder with your compiled program and execute ./program
Send the program, plus any .so files
.a is static library, .so is shared libraries.
Yes, but often you need to compile it yourself first.
Not sure about wxWidgets distributions, though.
Since Ubuntu comes with wxGTK packages you should definitely build against them. For development you should use a debug version though, so it might be good to build yourself, but for deployment building against the packages the system provides seems better.
wxX11 is a worse choice than wxGTK, use it only for systems where wxGTK doesn't exist or requires newer GTK libraries than are available.
Why not just stick with what you know and develop in .NET? Ubuntu comes native with Mono. You could keep using Visual C++ or step up to C# and make your life a whole lot easier.
A piece of general advice to Linux newcomers, but who are technically minded to begin with, is: You should learn to use your chosen distribution properly.
In your case, that means learning how to acquire the right development packages provided by Ubuntu. For instance, some other people are advising you to download the source for libraries you are going to use, but the better way is to use Ubuntu's package system to download the libraries you want to program against, together with the headers for that library (often put in a separate package) as well as the debug symbols for the library (also often in a separate package).
Look in the System->Administration menu in Ubuntu for the Synaptic tool, which allows you to search the package repositories on the Internet. You'll almost certainly find packages for the libraries you need, as well as all tools.
1, Unix generally doesn't have a particular extension for an executable - so myprog.exe would just be myprog.
You might have to set it to be executable if the IDE doesn't do this automatically, type "chmod +x myprog"
5, For wxWindows I would download the source and build it, check the build instructions but it's probably just a matter of "configure;make;make install". Generally in Unix you build libs form source so that they can correctly find all the components on your machine - you also have the source of examples etc.
I just added some information to rlbond's answer.
It is depens on Linux version. If you use a Ubuntu - create a deb-package. (http://ubuntuforums.org/showthread.php?t=51003)
Can I run wxGTK program under X11?
Yes, if you have wxGTK package installed :)
This is not really going to answer your questions, but I think is a valid recommendation.
You have two issues you are trying to deal with:
The Linux environment.
Making sure your program is
portable.
If I were you I would load CodeBlocks on Windows and run against either Cygwin or Mingw, that will help you make sure your code is portable across platforms. You are familiar with the environment and would gain maximum productivity getting over the OS hurdle.
Once you are satisfied with the above then take your code and move it to Linux. At that point any porting effort should be trivial.
When you say your program didn't show up I assume you mean that it was there in the file browser but when you double clicked it you got a busy cursor for a moment and then nothing happened?
If so then it means that the program failed to run, probably because it couldn't find the dynamic libraries it's linked against. To diagnose the problem you can run it from a terminal and then you'll be told what the problem is.
You might want to read the manual page for ld.so i.e. type
man ld.so
into a terminal. This tells you where the Linux dynamic library linker looks for libraries at run-time. It also refers you to another useful tool called ldd which I recommend becoming familiar with if your are doing Linux development.