I'm developing a cross-platform application that uses few shared libraries (also developed by me). I need to ensure that application is loading correct versions of that libraries at runtime. i.e. if user has specified path to some old version of shared library in config file application has to be able to detect this fact, do some logging and terminate. What is the best way to implement this? I'm sure that this problem is not new and there has to be some standart, "best-practice" solution.
The one solution I can think of is following:
Use version.h files in app and libs, during build step write same version values to both version.h files.
Implement getVersion() method in library, which will be used by application after loading library to ensure that library has expected version.
Any alternatives?
So I made a c++ console game. Now I'd like to "release" the game. I want to only give the .exe file and not the code. How do i go about this. I'd like to make sure it will run on all windows devices.
I used the following headers-
iostream
windows.h
MMSystem.h
conio.h
fstream
ctime
string
string.h
*I used namespace std
*i used code::blocks 13.12 with mingw
& I used the following library-
libwinmm.a
Thank you in advance
EDIT
There are many different ways of installing applications. You could go with an installer like Inno or just go with a regular ZIP file. Some programs can even be standalone by packaging all resources within the executable, but this is not an easy option to my knowledge for C++.
I suppose the most basic way is to create different builds for different architectures with static libraries and then find any other DLLs specific to that architecture and bundle it together in one folder. Supporting x86/x86-64/ARM should be enough for most purposes. I do know that LLVM/Clang and GCC should have extensive support for many architectures, and if need be, you should be able to download the source code of the libraries you use and then compile them for each architecture you plan to support as well as the compilation options you need to compile to each one.
A virtual machine can also be helpful for this cross-compilation and compatibility testing.
tldr; Get all the libraries you need in either static or dynamic (DLL) format. Check that they are of the right architecture (x86 programs/code will not run on MIPS and vice versa). Get all your resources. Get a virtual machine, and then test your program on it. Keep testing until all the dependency problems go away.
Note: when I did this, I actually had some compatibility issues with, of all things, MinGW-w64. Just a note; you may need some DLLs from MinGW, or, if you're using Cygwin, of course you need the Cygwin DLL. I don't know much about MSVC, but I would assume that even they have DLLs needed on some level if you decide to support an outdated Windows OS.
I have a bunch of python code that I would like to "compile" into a shared library with a C interface that can be linked with other C/c++ programs and work without depending on too many other libs (perhaps python and some other dlls but they should all be included into a directory with the final lib).
I don't really want to rewrite the python code into C++ for this. I can of course, but it would be best to have a standalone lib that can be used like a dll/so lib.
I have tried cython and wanted to compile python to C and then just compile C code into a dll but that doesn't seem to work quite yet (I haven't been able to make it work flawlessly yet). And then I also tried bbfreeze - but does bbfreeze support creating an .so file? Wasn't able to find out how to do it. Does anyone know?
Do you know of any other options that are more straightforward? the python code only needs to be compiled once. And best of all would be if it creates a single .so file no matter how big it is that just works without too many dependencies.
You can use Python as a library from inside your C++ application: it's called the Python/C API.
The idea is that you initialize your own interpreter, then you load a script in it. You can expose your C++ objects through global variables or modules inside the Python interpreter for your code to interact with, your you can just run Python functions directly from your C++ code.
Now, I understand that you might want to have your Python scripts embedded inside the shared library: this is not necessarily an easy task, with the traditional GNU toolchain. There are multiple techniques to achieve this, but none is official, and all seem way too complicated as opposed to just having the script in an external file.
If your goal is to hide the scripts from the end-user, you could sign them or encrypt them with a private key and embed the public key inside your library, but keep in mind that the key can easily be retrieved by anyone with enough motivation.
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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.
I have a C++ dll file that uses a lot of other c++ librarys (IPP, Opencv +++) that I need to load into matlab. How can I do this?
I have tried loadlibrary and mex. The load library does not work.
The mex finds the linux things (platform independent library) and tries to include them. And that does not work.
Does anyone have any good ideas?
loadlibrary should work. I use it all the time to call functions from dlls written in C++ with C wrappers.
What errors are you getting when you try to use loadlibrary?
Make sure that the exported functions of the dll are C functions, not C++ functions. If not, then write C wrappers.
More info on exactly what you are doing when using loadlibrary would be helpful.
As mentioned by others, you should first wrap your C++ library as a C library - mathworks used to advise not to use C++ code directly in mex (dlopening C++ core directly is complicated), maybe it is still true.
Your description is quite unclear, too: what do you mean by "mex finds the linux thing", but that does not work. Saying that it does not work is not helpful: the exact commands and error message are.
You could go for the Java approach (since Matlab runs on a JRE and can access Java objects/methods -- just be aware that the Matlab JRE is not as up-to-date as the latest JRE, the one I'm running uses Java 1.5) and use JNA to access your DLL.
Or, if you wrote the top-level DLL, you could go for the COM/ActiveX approach.
I've had good success architecting the interface to my C++ functions as COM/ActiveX libraries -- you don't have to bother with that .h stuff.
See the External Interfaces guide on COM clients, particularly the part about managing/converting data.
It would be extra work to add the COM/ActiveX layer, but would make your library more portable within the Windows world and probably more easily used in MATLAB.
If you have a lot of function calls to your DLL, the COM/ActiveX approach might be faster (not sure), but otherwise I think the JNA approach would be easier.