【Android】NDK的使用常见问题

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Android提供了NDK工具用以编译能够Android设备上运行的C/C++程序，本质上就是交叉编译，下面给出几篇关于NDK相关的文章。

教程

生成设备专用的toolchain

在 ${NDKROOT}/build/tools 下有两个脚本：make_standalone_toolchain.py 和 make-standalone-toolchain.sh，这两个脚本的功能相似，下面是脚本的使用方式（–help）：

usage: make_standalone_toolchain.py [-h] --arch
                                    {arm,arm64,mips,mips64,x86,x86_64}
                                    [--api API]
                                    [--stl {gnustl,libc++,stlport}]
                                    [--unified-headers] [--force] [-v]
                                    [--package-dir PACKAGE_DIR | --install-dir INSTALL_DIR]

Creates a toolchain installation for a given Android target. The output of
this tool is a more typical cross-compiling toolchain. It is indended to be
used with existing build systems such as autotools.

optional arguments:
  -h, --help            show this help message and exit
  --arch {arm,arm64,mips,mips64,x86,x86_64}
  --api API             Target the given API version (example: "--api 24").
  --stl {gnustl,libc++,stlport}
                        C++ STL to use.
  --unified-headers     Use unified headers.
  --force               Remove existing installation directory if it exists.
  -v, --verbose         Increase output verbosity.
  --package-dir PACKAGE_DIR
                        Build a tarball and install it to the given directory.
                        If neither --package-dir nor --install-dir is
                        specified, a tarball will be created and installed to
                        the current directory.
  --install-dir INSTALL_DIR
                        Install toolchain to the given directory instead of
                        packaging.

Usage: make-standalone-toolchain.sh [options] 

Generate a customized Android toolchain installation that includes
a working sysroot. The result is something that can more easily be
used as a standalone cross-compiler, e.g. to run configure and
make scripts.

Valid options (defaults are in brackets):

  --help                   Print this help.
  --verbose                Enable verbose mode.
  --dryrun                 Unsupported.
  --toolchain=<name>       Specify toolchain name
  --use-llvm               No-op. Clang is always available.
  --stl=<name>             Specify C++ STL [gnustl]
  --arch=<name>            Specify target architecture
  --abis=<list>            No-op. Derived from --arch or --toolchain.
  --ndk-dir=<path>         Unsupported.
  --package-dir=<path>     Place package file in <path> [/tmp/ndk-zonkin]
  --install-dir=<path>     Don't create package, install files to <path> instead.
  --dryrun                 Unsupported.
  --platform=<name>        Specify target Android platform/API level. [android-9]
  --force                  Remove existing install directory.

例如，我的平台是麒麟970，他是arm64的架构，Android版本是6.0（API 23），将生成的toolchain保存到 /tmp/ndk ，那么我只需要执行如下命令

./make_standalone_toolchain.py --arch=arm64 --api=23 --install-dir=/tmp/ndk

然后只需要设置好环境变量，即可开始使用交叉编译工具链：

export PATH=/tmp/ndk/bin:$PATH
export CC=aarch64-linux-android-gcc
export CXX=aarch64-linux-android-g++

常见问题

error: only position independent executables (PIE) are supported.

在编译时加入下面的选项

-pie -fPIE

参考：Android NDK 工具链的使用方法（Standalone Toolchain）