These are not installed on Android 4.2.1 by default, so is it possible to cross-compile the source for e.g. GNU grep or find and have it run on Android? ( Preferably without having to root the device or installing some app off PLAY e.g. busybox.) Are there any missing dependencies that will prevent this? I am developing on Ubuntu 10.0.04
Strange. I have them on /system/xbin/*. Maybe more luck with busybox. busybox find busybox grep Not sure if busybox is installed by default on Android 4.2 tho, but it's a pretty common binary.
This is not a complete answer because I haven't tried building grep or find. However, in general it is quite possible to build GNU utilities for Android. To do this, the best option is:
Download the Android native development kit
Build an Android standalone toolchain by referring to docs/STANDALONE-TOOLCHAIN.html in the NDK
Simply build the relevant GNU utility using the normal ./configure && make mechanism.
You'll then need to copy the resulting binaries onto your Android device, which you can do using adb push. You may need to arrange to put them into /data/ somewhere because /mnt/sdcard is often marked non-executable.
Missing dependencies
The main problem you'll find during the actual builds is that Android does not use the standard GNU libc (glibc). Instead, it uses its own, called Bionic. This does miss certain important APIs - for example, wide character string support.
I've found for some GNU utilities this is OK and they can be compiled with minimal source code changes.
However, if you run into trouble, you're probably better off using other versions of these utilities which are typically designed for more flexibility in terms of the underlying libc. Specifically, the previous advice about using busybox is excellent. If you don't wish to install it from the Android market, you can find the source code here.
Related
I want to run an application based on Qt5 shared objects.
Although I have apt installed qt5-default, qttools5-dev and qttools5-dev-tools I get the error bellow:
/usr/lib/x86_64-linux-gnu/libQt5Core.so.5: version `Qt_5.7' not found
/usr/lib/x86_64-linux-gnu/libQt5Core.so.5: version `Qt_5' not found
/usr/lib/x86_64-linux-gnu/libQt5Gui.so.5: version `Qt_5' not found
/usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5: version `Qt_5' not found
I have also tried to change some environment variables as LD_LIBRARY_PATH and DYLD_LIBRARY_PATH, resulted in no success!
What do you suggest?
When you built your application, which version of Qt5 did you build against? You can see this in QtCreator by looking at the currently selected kit:
If you just installed QtCreator from binary, it is shipped with it's own set of Qt5 shared libraries that your application is linked against, however your OS' version of those libraries (those installed from apt-get and similar) may not match.
When you try to run the application on it's own outside QtCreator, it may try to link against the OS version of the libs which are usually much older.
There are many ways to resolve this. One way, which would be preferred if you don't care for the newest version of Qt, is simply building towards the Qt libs supploed by the OS. You can do this by creating a new kit that specifies to build against the OS' libraries following this procedure.
Another way is shipping the shared libraries that you used from QtCreator together with the application so that those will override the OS ones. Usually just chucking them into the same folder as the executable will do the trick, as they will be found before the ones under /usr/lib/whatever etc.
Yet another way is to build your own static version of Qt and link with that. This has some benefits and some drawbacks. This is an advanced topic, so I won't go into detail (you can see here). But in this case the Qt libs are built into your app and will not depend on any external Qt libs version.
I am trying to get memcached running on Windows. I have downloaded memcached stable latest and compiled it using Mingw under Windows 7. Configure failed with error,
checking for libevent directory... configure: error: libevent is
required. You can get it from http://www.monkey.org/~provos/libevent/
If it's already installed, specify its path using --with-libevent=/dir/
Then I downloaded libevent and compiled it. This produced 3 DLLs, libeventcore, libevent-extra and libevent-2.0.5.
I ran configure on memcached again with the option --with-libevent. But for some reason, it fails again with the same error. I have no clue on why it is failing. Can anyone help me to resolve this issue? Or is there a better way to get memcached running on Windows? I have seen lot of pre-built binaries for Windows. But all of them uses old versions of memcached. And AFAIK, Windows is officially supported by memcached in the newer versions.
I am using Windows7 64bit version with MinGW.
After you run make in libevent dir you get the files ready, but to make full use of it, they must be installed. So make install step is needed. If you configured it with a prefix, it will land in the directory of your choice. Otherwise it is /usr/local.
So maybe it's enough to run make install in libevent dir and run configure from memcache without parameters.
If you still have problems passing the configure stage, look at config.log. It shows the source file and the gcc command on which it failed.
Unfortunately successful configure is not everything. Later it fails on inclusion of sys/socket.h, netinet/in.h and netdb.h and perhaps also -pthread gcc parameter. I'm afraid it won't compile on mingw. At least not without a serious porting effort.
As I know, Never had an official Memcached port for Windows (Yes, there were few individual efforts. Last knowing porting effort can find on version 1.2.6 here) Best known Implementation for Memcached for windows on Couchbase with Memcached Bucket.
Late to the party I realize but the answer is to use:
$ export LIBS=-lws2_32
which will place $LIBS at the end of compile calls so that it is linked to libws2_32.a or winsocks2, but this probably means that your did not configure your build correctly and you will subsequent errors such as #include <sys/socket.h> header not found, etc.
see mingw-linker-error-winsock
I'm working on AOSP 4.0.4 branch and doing some customizations for the PandaBoard platform. I was looking at the ARM cross-toolchains being used to build the Android filesystem images, and I see 2 major variants.
arm-eabi-4.x (set in ARM_EABI_TOOLCHAIN env var)
arm-linux-androideabi-4.x (set in ANDROID_EABI_TOOLCHAIN env var)
I have searched a lot of places, and could not find any information regarding the toolchains.
By the naming convention, I'm guessing the following - are these correct ?
arm-eabi- is a bare-metal toolchain
arm-linux-androideabi- is the one used to build all the native code in AFS linked against bionic libc as well as the toolchain used for the NDK.
Could someone give me examples of code in the AOSP tree using the bare-metal toolchain (other than for u-boot, x-loader, kernel - all of which are built in a separate tree) ?
I'm going to be doing minor modifications to these toolchains, and hence require rebuilding them. Could someone point me to the repositories and build instructions for these toolchains ?
Yes you are right. arm-eabi- is a bare metal toolchain and used to build u-boot for instance.
I am not sure if there is any
I could not find arm-linux-androideabi-4.x to be precise but you may have a look at this link: https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/arm/
I hope it helps :)
I am trying to create a development environment on my host machine that is identical (or as close to as possible) to the one on my embedded device using a chroot. Both host and target machines are x86 so I am not attempting to cross compile. I want to build GCC in my chroot and then using build libc and any other libs that are already on my embedded device (as well as any others that my executable will need to run in order to deploy on the device). In this way I am hoping to have all of the libs on my dev machine correctly linked with the appropriate version of libc.
My question is this - I know that the libc on the embedded device is 4.3.2 but how important is it that I use the same version of GCC to build the libraries locally on my dev machine?? Are there any potential complications if I actually use a more recent version (i.e. the one that came with my dev machine install which is 4.6.3) to build these libs??
As long as the ABI has not changed between compiler versions, you should be fine. From the back of my head, the C ABI hasn't changed in ages, and the C++ ABI not since 3.4 / 4.0. Check the official docs to be sure.
gcc 4.4.4 c89 Fedora 13
I am wondering what is better. To give you a compile of examples: apache runtime portable and log4c.
The apr version in my fedora repository is 1.3.9. The latest stable version on the apr website is 1.4.2.
Questions
Would it be better to download from the website and install, or install using yum?
When you install from yum sometimes it can put things in many directories. When installing from the tarball you can put the includes and libraries where you want.
The log4c the versions are the same, as this is an old project.
I downloaded log4c using yum. I copied all the includes and libraries to my development project directory.
i.e.
project_name/tools/log4c/inc
project_name/tools/log4c/libs
However, I noticed that I had to look for some headers in the /usr/include directory.
Many thanks for any suggestions,
If the version in your distribution's package repository is recent enough, just use that.
Advantages are automatic updates via your distribution, easy and fast installs (including the automatic fetching and installing of dependencies!) and easy removals of packages.
If you install stuff from .tar.gz by yourself, you have to play your own distribution - keep track of security issues and bugs.
Using distribution packages, you have an eye on security problems as well, but a lot work does the distributor for you (like developing patches, repackaging, testing and catching serious stuff). Of course each distributor has a policy how to deal with different classes of issues for different package repositories. But with your own .tar.gz installs you have nothing of this.
It's an age-old question I think. And it's the same on all Linux distributions.
The package is created by someone - that person has an opinion as to where stuff should go. You may not agree - but by using a package you are spared chasing down all the dependencies needed to compile and install the software.
So for full control: roll your own - but be prepared for the possible work
otherwise use the package.
My view:
Use packages until it's impossible to do so (conflicts, compile parameters needed, ..) . I'd much rather spend time getting the software to work for me, than spend time compiling.
I usually use the packages provided by my distribution, if they are of a new enough version. There is two reasons for that:
1) Someone will make sure that I get new packages if security vulnerabilities in the old ones are uncovered.
2) It saves me time.
When I set up a development project, I never create my own include/lib directories unless the project itself is the authorative source for the relevant files I put there.
I use pkg-config to provide the location of necessary libraries and include files to my compiler. pkg-config use some .pc-files as a source of information about where things are supposed to be, and these are maintained by the same people who create the packages for your distribution. Some libraries does not provide this file, but an alternative '-config'-script. I'll provide two examples:
I'm not running Fedora 13, but an example on Ubuntu 10.04 would be;
*) Install liblog4c-dev
*) The command "log4c-config --libs" returns "-L/usr/lib -llog4c" ...
*) The command "log4c-config --cflags" returns "-I/usr/include"
And for an example using pkg-config (I'll use SDL for the example):
*) Install libsdl1.2-dev
*) The command "pkg-config sdl --libs" returns "-lSDL"
*) The command "pkg-config sdl --cflags" returns "-D_GNU_SOURCE=1 -D_REENTRANT -I/usr/include/SDL"
... So even if another distribution decides to put things in different paths, there are scripts that are supposed to give you a reliable answer to where things is - so things can be built on most distributions. Autotools (automake, autoconf, and the likes) amd cmake are quite helpful to make sure that you don't have to deal with these problems.
If you want to build something that has to work with the Apache that's included with Fedora, then it's probably best to use the apr version in Fedora. That way you get automatic security updates etc. If you want to develop something new yourself, it might be useful to track upstream instead.
Also, normally the headers that your distro provides should be found by gcc & co. without you needing to copy them, so it doesn't matter where they are stored by yum/rpm.