在Android上运行C代码而无需编译整个树

Question

I have a C code which I want to add to the Android C libraries.

I can build and execute the coed when I am compiling the entire android tree.
I would like to be able to add the code to an existing compiled android environment. ie To use a built device and just push my application and execute it there.

I succeeded to compile my code on windows platform for linux using the NDK and to push it using adb push command.

When trying to execute using the adb execute

I get the following error:

[Android] not executable: magic=7F45

Answer 1

Magic 7F45 means the binary is a linux ELF and is not compiled to the ARM arch (you can find out what arch using file ). You need to create the standalone toolchain using the NDK and then use it to build the correct binaries.

Here are the main details of how you do this courtesy of the android dev site :

The NDK allows you to create a "customized" toolchain installation to make life easier. For example, consider the following command:

$NDK/build/tools/make-standalone-toolchain.sh --platform=android-5 --install-dir=/tmp/my-android-toolchain 

This will create a directory named /tmp/my-android-toolchain containing a copy of the android-5/arch-arm sysroot, and of the toolchain binaries.

Note that by default, the ARM-based toolchain will be selected by the script.
Use the '--arch=x86' option to specify the x86-based one,
use the '--arch=mips' option to specify the MIPS-based one, or alternatively '--toolchain='.

You can later use it directly with something like:

export PATH=/tmp/my-android-toolchain/bin:$PATH 
export CC=arm-linux-androideabi-gcc

The environment variables shown above allow you to make use of configure or make to build 3rd party code for the arch you specified. You may of course just use the compiler directly.