Whats the best procedure to cross compile lua and libs (luasockets, orbit, etc) for an embedded arm device.
Im able to succesfully cross compile lua interpreter, but from there im a little bit lost.
I started using this repo as a base some years ago: https://github.com/johnhw/luajitpi
The whole process depends on what OS your device is running and how POSIX-ish it is. If your system provides a BSD-like-socket API the process should be trivial.
The same applies for pthreads and other APIs your OS should provide. We're running eCos for example, which has a small POSIX layer so the porting of libs like luasocket was easy.
Related
I've been working with a teensy for a multithreaded project using openmp compiling with gcc, however I'm joining a project that uses avr-gcc which doesn't seem to want to compile or recognize omp.h . I get the error "avr-gcc: error: unrecognized command line option '-pthread' " when I attempt to compile and am having trouble finding more information. I found this question about gcc-avr having slower updates AVR gcc version < gcc release versions -- why? but am wondering if avr-gcc hasn't yet added openmp support or doesn't for one reason or another and if there's a work around without requiring the team to switch compilers.
thanks for the direction it appears that avr-gcc doesn't provide headers that interact with operating systems which apparently pthreads does.
"Since sockets are a feature provided by the operating system, and you are compiling code that runs bare-metal on an Arduino microcontroller, which has no operating system running on top, the whole purpose of the sys/socket.h header is nullified.
This applies to any other kind of header or library function that interacts with the operating system, such as unistd.h, fcntl.h, pthread.h etc. In fact, avr-libc, the Standard C library for AVR-GCC, does not provide such headers.
You will need to look at the avr-libc documentation to find out more about the headers and functions that are provided and their usage."
I am using OpenCv 2.4.3. I just downloaded it from their site and used the build that they have made. I did not want to take the headache of building it from the source myself. Anyway, in my machine the haar classifier gives very slow performance to detect faces. In another machine my friend runs it fine.( he built from source with TBB and IPP supprt on in cmake).
Though in the release they say that : "You do not need TBB anymore on MacOSX, iOS and Windows. BTW, the binary package for Windows is now built without TBB support. Libraries and DLLs for Visual Studio 2010 use the Concurrency framework."
I do not know much about these TBB and IPP. Only thing that I understand is making these things available will make multi-threading and parallelism possible resulting to speeding up my program.
Do I need to compile the source with cmake, TBB IPP bla bla... or there is something else that I am missing? Any ideas?
What they say, is that they have the pre-built binaries compiled in a way that does not need TBB, because they use another concurrency framework. So if You don't want to meddle in the library's settings You can use the pre-built version without sacrificing performance. But that is on Windows, iOS and MacOS.
The performance might also depend on the machines parameters (You know, cascades are power hungry), so if Your friend has a stronger machine, he will probably get better results, and OS You are operating, but I cannot tell You which is the best, as I didn't try OpenCV on anything besides Linux.
How can I build and compile my own Lua files on Windows? And make them executable.
I am reading Beginning Lua programming, and I have Windows 7 and MacOS Lion both installed. I am having the hard time to follow the instructions. They do not work for me.
On MacOS I open the terminal and put these in:
export LUA_DIR=/usr/local/lib/lua/5.1
mkdir -p /usr/local/lib/lua/5.1 (it tells me, mkdir: illegal option) and I can not follow from here
SET LUA_DIR=”c:\program files\lua\5.1”
As for Windows I do this according to the book.
This what I see in my shell c:\Users\bd>
mkdir "c:\program files\utility" and it tells me access is denied
I have tried to right click on this folder and check off read only, but it does not work.
Any clues would be appreciated, this part has been really confusing for me.
To package your Lua files into an executable on Windows you have several options. There is srlua, there is wxLuaFreeze from wxLua (available as a binary for Windows), and there are more options in this SO answer.
Essentially, the main two options are: (1) append your Lua code to a precompiled exe file, such that it will be loaded and executed when that exe file is run, and (2) convert your Lua code into real executable by compiling it to bytecode, then to C, and then to your target platform.
As to your MacOS issue, mkdir -p means that mkdir is asked to create intermediate directories (for example, you asked to create /a/b/c, it will also create /a/b if those don't exist). As you don't say which version of MacOS you run, it's difficult to provide more detailed answer.
For now the standard distribution of Lua does not compile a script to native executable code; it execute your scripts by first compiling it to bytecode, then by interpreting the bytecode with a reasonnably fast static interpret (this also means that it is easily portable across native or virtual systems, and very resistant to attacks (that could be targetting bugs in the native compiler itself).
Also Lua still does not feature a runtime JIT compiler like Java and .Net: Lua still does not features a VM to produce a safe sandbox.
There exists Lua packages that convert your bytecode (or directly a source script) to a C source that can be used to convert a Lua library into native mode via the same C compiler used to compile the Lua engine itself (this is how the builtin libraries are produced, though they are slightly optimized manually in some time-critical parts).
However it is possible to compile Lua to a javascript source, and run it with fast performance using Javascript, because today's Javascript interprets do have good performance with their implemented VM featuring a JIT compiler for their own bytecodes.
It is also possible by converting it the Lua bytecode to a .Net or Java source that can then be executed directly from Lua (for that you need a version of Lua that has been ported to .Net or Java or Javascript, something that is not so complicate than developing in C/C++ directly a VM with a JIT compiler (a moderately complex part is the bytecode verifier, but the really complex part is the memory manager its garbage collector and its sandbox so that your Lua script will be fully isolated from the Lua engine itself for itw own memory, but the most complex part if the runtime optimizer and collection of profiling statistics: this has been done in the modern VMs for Java, .Net, Javascript, PHP/Zend, Python, Perl...).
I dont know which other language VM would offer the best performance to port Lua and implement on it a compiler to their own bytecode running at near native speed in their VM. But my own small experience with programs (in a much simpler language) self-generating a bytecode that they can run themselves, has always shown me Java winning in performance over .Net and Javascript. This is most probably because Java features an profiling-based dynamic code optimizer
(On the opposite the .Net optimizer runs only once during program installation, using some profiling data collected during the installation of the .Net VM itself, or at first instanciation of the script, without really knowing any profiling data collected during execution of the compiled program itself, and based on some cheked assumptions about the platform capabilities).
I also don't if would be faster in PHP, Python or Perl; the comparison with newer Javascript engines was never attempted though. Porting/compiling a Lua program to Javascript is relatively easy because it implements closures relatively easy for the resolution of linkages. Then the generated Javascript will compile to native code with the excellent Javascript's JIT compilers we have today (and never cease to improve in performance, so much that I've seen various appliactions running now faster in Javascript than before when they were written in C++ or plain C; as well the memory footprint has largely been reduced, we no longer have memory leaks, and even if there's a garbage collector, today's Javascript VM have a very efficient one, which is even better than the GC implemented in the native Lua).
But Lua remains useful as it is easy to secure and sandbox and offers various security benefits (but there are security issues in Lua as well for some kinds of applications, where Javascript offers some solutions, notably for side-channel attacks based on variation of time of execution; but these side-channel attacks are very hard to solve and can affect any system, any program, any programming language, and this starts becoming a critical issue because they are now more esily exploitable; the reason of that comes from hardware optimizations that we depend more and more today when we want to maximize the performances). And with Lua you may be more immune to these problems that a sandboxing sofware environment cannot solve alone.
Probably later we'll see a true VM implementation of Lua with a JIT and self-generating code and the possibility to instanciate new sandboxed VMs to run their self-generated code. It will take more time to generate an EXE file for distribution; notably because it generally requires adding also an installer and a distribution manager.
So for now we could imagine distributing Lua applications compiled to the bytecode of another JIT-capable VM: this generated bytecode would be faster than the Lua bytecode, and would then be extremely complex to reverse-engineer to the semantics of Lua because it would require two separate reverse engineering first from the bytecode of the other VM to the bytecode of Lua, both bytecodes loosing some easiy inferable rules and options tested and foll, and then again to sme Lua source
For the OSX terminal issue:
This command should work
export LUA_DIR=/usr/local/lib/lua/5.1
This command will probably give you permission problems:
mkdir -p /usr/local/lib/lua/5.1
You may try this to solve that. You will be prompted for your password:
sudo mkdir -p /usr/local/lib/lua/5.1
This command has nothing to do with OSX and will not work. This is a windows command:
SET LUA_DIR=”c:\program files\lua\5.1”
You have a permissions problem with Windows- try creating your cmd or PowerShell in Administrator mode. C:\Program Files is a protected directory that a regular user account doesn't have permission to write to.
As for the OS X issue, check out the mkdir OS X manual page to make sure you have the command correct.
So, if I understood your question correctly, you are trying to build Lua on Windows.
This is of course possible, but not easy for beginners. I would highly recommend you to use a binary distribution, which is much easier to install, unless you have special requirements.
Here are several Windows distributions :
Lua Binaries (Lua 5.1 and 5.2)
LuaForWindows (Lua 5.1)
LuaDist (Lua 5.2)
Question: How do make a single make file to compile several different systems, environments, and sets of libraries at once?
Info:
I'm a student and as such most of my work is done for the sake of learning how these things work. Right now I'm building a game engine from the ground up. I'd like to be able to make it cross platform in terms of OS, but also for different environments. My target environments are both 32 and 64 bit (my desktop as well as my netbook), with a graphics card and with mesa, and linux and windows. so overall it should out put 8 binaries.
I'm still very new to make, as well as the whole concept of cross compiling. I imagine that the process of compiling more than 1 binary isn't hard. but where I'm kind of stuck is how do i get it to attach the right libraries? The Ubuntu Linux vs the WinAPI libraries, 32bit vs 64bit libraries. etc etc. Is it even possible to get libraries in such a manner?
If you need me to clarify further I can. Thanks.
Addendum: Basically I want to know how to compile headers for drivers i may not have. for example. I want to compile all the files on my netbook, including the ones for openCL, I don't want to run them, as my netbook has no GPU, I just want to compile. conversely, I want to use my desktop compile for my netbook which uses ocelot and mesa for its gpu dealings, but my desktop does not have mesa or ocelot on it. that sort of thing. Thanks.
I downloaded Lazarus, but have worked with Embarcadero Delphi IDE too. I have a question about building cross-platform Delphi applications.
How can I build them under win32 environment? I read the wiki from Lazarus site, that explains how to do it, but I still do not understand it. Is is possible to build and compile application under win32 environment for Linux and MacOS? If it is possible, can someone explain ste-by-step how to do it exactly.
EDIT:
Now is the time for talking about the new XE2 version of the Delphi IDE I think :)
Thanks
What you're asking for already exists in the lazarus wiki site, you need to read these articles.
Multiplatform Programming Guide
Cross compiling
Cross compiling for Win32 under Linux
How to Write Portable Code (nice doc from Marco van de Voort)
Buildfaq
While crosscompiling to a non windows target is possible (and not that hard), getting used to fpc/lazarus and crosscompiling in one first step is a bridge too far. This because Linux is not a very homogenous target and dealing with this variation requires some understanding how libraries and linking works on Linux. This defeats one-button downloadable cross-compile setups to "general" linux. I know, such one-button thingies that work out of the box for everyone would be great, but it is just not going to happen (or only forvery limited distribution-version combinations)
Crosscompiling with FPC is not extremely difficult or rocket science, but the amount of jargon and details can flabbergast uninitiated people, and without background knowledge it is hard to diagnose problems as a result of minor misconfigurations
I recommend to first familiarize yourself with Lazarus/FPC, and only then make the crosscompilation leap. (and the already mentioned buildfaq names some reasons).
Bottomline: install lazarus on Windows and start porting your app. If that succeeds, start using a linux install (or VM) to familiarize yourself with Linux, and Lazarus under it. You'll need a linux install anyway to test.
Only then start thinking about crosscompiling to speed up the process.
CodeTyphon is a powerful Lazarus/FPC one click easy installation package for cross platform native development. It already supports 4 CPU/OS hosts (Win32, Win64, Linux32, Linux64), and 16 CPU/OS targets (arm-Wince, arm-Linux, arm-Embedded, arm-gba, arm-nds, i386-Win32, i386-Linux, i386-FreeBSD, i386-Haiku, x86_64-Win64, x86_64-Linux, x86_64-FreeBSD, powerpc-Linux, powerpc64-Linux, sparc-Linux, sparc-Solaris). More are supported in Lazarus/FreePascal, but others are not yet integrated in CodeTyphon. Did I mention that it is free? One code to rule them all ;-)
The point is that you don't have to waste days for setting up your cross platform environment, since someone has already done the hard work for you.