I want to develop a web app for an embedded system. It is very easy to do so in python or java. However, I have two major problems:
I have a very limited space available on my embedded device
I cannot figure out how to include a python interpreter in the openembedded
framework.
Does anyone know how to cross compile python with openembedded?
If you have already got an openembedded project running, in arago-oe-dev project, the arago-oe-dev/recipes/ directory includes python.
Then you need to include python into your own dependency tree of recipes. Normally on the top level of dependency tree is the "Images" recipe in which you define what are included into you embedded firmware image to be running on your embedded device.
In the .bb file of "Images" recipe, you normally find a variable of IMAGE_INSTALL. You can add your app recipe into IMAGE_INSTALL.
Then in your recipe of you app, in its .bb file, you should add python to something like "RDEPENDS_${PN}" to add it to run-level dependency. Don't forget to inherit the pkgconfig bbclass so that the runtime linking is properly managed. Then the python library (.h and .so or .a files) will be built into your firmware image in something link /usr/lib and /urs/incluce and be linked by the embedded apps you develope.
You need to edit the image recipe to include python and any needed modules in the image. python is the package name for the python interpreter.
Related
I am working on a library that provides gdb pretty-printers. They could be automatically located by including the .debug_gdb_scripts section in the generated binary. For binaries inside build, I would like this section to point to the pretty-printer inside the source tree. For installed binaries, I would like to either strip this specific section only, or install the pretty-printer as well and change the reference to its installed location.
Is there builtin functionality in CMake or a simple solution to postprocess the installed binary?
I have a "cross platform" application that uses two code repositories at the moment, maintained relatively independently, and built with VS / Xcode depending on the target platform (win or mac respectively). I fell in love with Premake after using it on a few previous projects and am trying to pull all of my code for this application together into a single cross-compilable codebase.
I don't want to rely on Xcode, and instead want any developer to be able to build on Mac using either Xcode or gmake. I have a non-standard framework that I want to link to and include in the repository (it won't be located in /Library/Frameworks or any of the default mac framework search paths). I've added the framework file in a directory in my project /lib/TheFramework.framework. My premake file contains the following under the project definition:
includedirs {".", "lib", "lib/TheFramework.framework/Headers"}
libdirs {"lib"}
links {"TheFramework.framework"}
When I compile, (running $ premake5 gmake and then $ make), I get a header file not found error. Is there something wrong with my search paths? Am I missing a path or a flag somewhere?
Thanks!
Before looking at what you need to do with premake, let's first look at what needs to happen under the hood.
When compiling a mac program with a non-standard framework on gcc or clang (which is what your resulting make file does) it is necessary to do two things:
Specify the name of the framework, via -framework TheFramework - This is what premake does when you provide it with links {"TheFramework.framework"
Specify the location of the framework, via -F /Path/To/Framework/ - This is currently not being handled automatically by premake.
I've made a simple test c program that uses the SDL2 framework and compiled it with gcc: https://gist.github.com/JohannesMP/6ff3463482ebbdc82c2e - notice how when I leave off the -F /... flag I get an error that is probably similar to what you described.
So what is happening is, although you are providing premake with the include dir, premake will not add that the proper -F flag.
One way around this is to do the following:
configuration {"macosx", "gmake"}
buildoptions {"-F /Path/To/Framework"}
linkoptions {"-F /Path/To/Framework"}
(See here for an example project: https://gist.github.com/JohannesMP/9a9b5263c127103f1861#file-premake5-lua-L24-L26 )
In premake5 this will blindly append the code provided to both the build step as well as the link step. It is necessary to do it both for build as well as link.
Just keep in mind that, because premake doesn't process or check the build/link options for being valid, a user will receive an error if the provided path doesn't exist on their machine. For example while you might have a framework in your user-specific directory ~/Library/Frameworks, since that folder doesn't exist by default another user might be using the global /Library/Frameworks instead, and when they try to compile your premake project with gmake they will get a warning:
ld: warning: directory not found for option '-F/Users/<NAME>/Library/Frameworks'
At this point, it seems that there is no 'safe' way to get premake5 to try to include the framework path, but that may change in the future.
Check out this issue I posted on the premake repo: https://github.com/premake/premake-core/issues/196
I have built a Qt project under mac, but I have problems executing.
Its dependencies have several dylib .
When building the project, the make tool only asks for one of the libs (for example lib.1.0.0,dylib out of lib.1.dylib, lib.1.0.dylib, lib.1.0.0.dylib, lib.1.0.0.0.dylib) - so I know to put it in the .pro file
Some look like links - but it is not always the lib version that looks like a file that is required as a dependency.
But at run time, I don't know which dylib I need, and where to put it.
I tried to place all 4 lib versions in the folder where the app was created - the project folder - but the app didn't execute.
Having done the same in Linux, I had to put the libs in a place set on path - like /usr/local/libs
Where does mac like its libs (shared libs ?) in order to run ?
You should read this document on deploying Qt applications. It will answer your questions. Moving your libraries to a system library path is usually not a good idea.
http://qt-project.org/doc/qt-5/macosx-deployment.html
To sum this up though you need to change the binaries to tell them where the libs are using the otool command.
I compiled various Linux kernel from git repositories. There are times when I copied the kernel to other system and need the kernel header to compile external module.
I tried to run "make headers_install" but it only generated a include/ folder. When I tried to point external module to that folder, it complains it cannot find Makefile.
What is the proper way to package kernel-header for deployment?
Thanks.
Create kernel packages instead, that's "make deb-pkg" for dpkg based distros and "make rpm-pkg" for RPM based ones. These create multiple packages, one of those is a package usable for external modules building. That should be linux-headers-* for the Debian packages and a "devel" package for he RPM versions.
In some ways this is just an expansion of the previous answer. If you look at the file scripts/package/builddeb in the kernel sources you will find script code which selects the files needed for building external modules from a kernel build and puts them into /usr/src/linux-headers-$version. I can find that script code in my local kernel version by searching for the string "# Build kernel header package" in the builddeb file. If you want to do things by hand you could execute that script code manually.
I'm trying to get something of an environment on a usb stick to develop C++ code in. I plan to use other computers, most of the time linux, to work on this from a command line using g++ and make.
The problem is I need to use some libraries, like Lua and OpenGL, which the computers don't have. I cannot add them to the normal directories, I do not have root on these computers. Most of the solutions I've found involve putting things in /usr/lib/ and the like, but I cannot do that. I've also attempted adding options like '-L/media//lib', which is where they are kept, and it didn't work. When compiling, I get the same errors I got when first switching to an OS with the libraries not installed.
Is there somewhere on the computer outside of /usr/ I can put them, or a way to make gcc 'see' them?
You need more than the libraries to be able to compile code utilizing those libraries. (I'm assuming Linux here, things might be slightly different on e.g. OSX,BSDs,Cygwin,Mingw..)
Libraries
For development you need these 3 things when your code uses a library:
The library header files, .h files
The library development files, libXXX.so or libXXX.a typically
The library runtime files , libXXX.so.Y where Y is a version number. These are not needed if you statically link in the library.
You seem to be missing the header files (?) Add them to your usb stick, say under /media/include
Development
Use (e.g.) the compiler flag -I/media/include when compiling source code to refer to a non-standard location of header files.
Use the compiler/linker flag -L/media/lib to refer to non-standard location of libraries.
You might be missing the first step.
Running
For dynamically linked libraries, the system will load those only from default locations, typically /lib/ , /usr/lib/
Learn the ldd tool to help debug this step.
You need to tell the system where to load additional libraries when you're running a program, here's 3 alternatives:
Systemwide: Edit /etc/ld.so.conf and add /media/libs there. Run ldconfig -a afterwards.
Local, to the current shell only. set the LD_LIBRARY_PATH environment variable to refer to /media/lib, run export LD_LIBRARY_PATH=/media/lib
Executable: Hardcode the non-standard library path in the executable. You add this to the linking step when creating your executable: -Wl,-rpath,/media/lib
Etc.
There could be other reasons things are not working out, if so,
show us the output of ls -l /media/libs , and where you put the library header files, the command line you use to compile/link, and the exact errors you get.
Missing the headers and/or development libraries (for dynamic libraries there is usually a symlink from a libXXX.so to a libXXX.so.Y , the linker needs the libXXX.so , it will not look directly at libXXX.so.Y)
using libraries not compatible with your current OS/architecture. (libraries compiled on one linux distro is often not compatible with another distro, or even another minor version of the same distro)
using an usb stick with a FAT32 filesystem, you'll get in trouble with symlinks..