ndk=true ndk.win_download=android-ndk-r8b-windows.zip ndk.win_bytes=188724991 ndk.win_checksum=6d290d4f2729ef2063c5ae5b1e335622 ndk.mac_download=android-ndk-r8b-darwin-x86.tar.bz2 ndk.mac_bytes=181255568 ndk.mac_checksum=94fe392194ea41f8a70cfce0dee3870f ndk.linux_download=android-ndk-r8b-linux-x86.tar.bz2 ndk.linux_bytes=160466240 ndk.linux_checksum=6694ccc04d543500f0661a75f6c46526 page.title=Android NDK @jd:body

In this document

  1. Downloads
  2. Revisions
  3. System and Software Requirements
  4. Installing the NDK
  5. Getting Started with the NDK
    1. Using the NDK
  6. Contents of the NDK
    1. Development tools
    2. Documentation
    3. Sample apps

The NDK is a toolset that allows you to implement parts of your app using native-code languages such as C and C++. For certain types of apps, this can be helpful so that you may reuse existing code libraries written in these languages and possibly increased performance.

Before downloading the NDK, you should understand that the NDK will not benefit most apps. As a developer, you need to balance its benefits against its drawbacks. Notably, using native code on Android generally does not result in a noticable performance improvement, but it always increases your app complexity. In general, you should only use the NDK if it is essential to your app—never because you simply prefer to program in C/C++.

Typical good candidates for the NDK are self-contained, CPU-intensive operations that don't allocate much memory, such as signal processing, physics simulation, and so on. When examining whether or not you should develop in native code, think about your requirements and see if the Android framework APIs provide the functionality that you need.

Downloads

Revisions

The sections below provide information and notes about successive releases of the NDK, as denoted by revision number.

Android NDK, Revision 8b (July 2012)

The main features of this release are a new GNU Compiler Collection (GCC) 4.6 toolchain and GNU Debugger (GDB) 7.3.x which adds debugging support for the Android 4.1 (API Level 16) system image.

Important bug fixes:
  • Fixed {@code LOCAL_SHORT_COMMANDS} issues on Mac OS, Windows Cygwin environments for static libraries. List file generation is faster, and it is not regenerated to avoid repeated project rebuilds.
  • Fixed several issues in {@code ndk-gdb}:
    • Updated tool to pass flags {@code -e}, {@code -d} and {@code -s} to adb more consistently.
    • Updated tool to accept device serial names containing spaces.
    • Updated tool to retrieve {@code /system/bin/link} information, so {@code gdb} on the host can set a breakpoint in {@code __dl_rtld_db_dlactivity} and be aware of linker activity (e.g., rescan {@code solib} symbols when {@code dlopen()} is called).
  • Fixed {@code ndk-build clean} on Windows, which was failing to remove {@code ./libs/*/lib*.so}.
  • Fixed {@code ndk-build.cmd} to return a non-zero {@code ERRORLEVEL} when {@code make} fails.
  • Fixed {@code libc.so} to stop incorrectly exporting the {@code __exidx_start} and {@code __exidx_end} symbols.
  • Fixed {@code SEGV} when unwinding the stack past {@code __libc_init} for ARM and MIPS.
Important changes:
  • Added GCC 4.6 toolchain ({@code binutils} 2.21 with {@code gold} and GDB 7.3.x) to co-exist with the original GCC 4.4.3 toolchain ({@code binutils} 2.19 and GDB 6.6).

    • GCC 4.6 is now the default toolchain. You may set {@code NDK_TOOLCHAIN_VERSION=4.4.3} in {@code Application.mk} to select the original one.
    • Support for the {@code gold} linker is only available for ARM and x86 architectures on Linux and Mac OS hosts. This support is disabled by default. Add {@code LOCAL_LDLIBS += -fuse-ld=gold} in {@code Android.mk} to enable it.
    • Programs compiled with {@code -fPIE} require the new {@code GDB} for debugging, including binaries in Android 4.1 (API Level 16) system images.
    • The {@code binutils} 2.21 {@code ld} tool contains back-ported fixes from version 2.22:
      • Fixed {@code ld --gc-sections}, which incorrectly retains zombie references to external libraries. (more info).
      • Fixed ARM {@code strip} command to preserve the original {@code p_align} and {@code p_flags} in {@code GNU_RELRO} section if they are valid. Without this fix, programs built with {@code -fPIE} could not be debugged. (more info)
    • Disabled {@code sincos()} optimization for compatibility with older platforms.
  • Updated build options to enable the Never eXecute (NX) bit and {@code relro}/{@code bind_now} protections by default:
    • Added {@code --noexecstack} to assembler and {@code -z noexecstack} to linker that provides NX protection against buffer overflow attacks by enabling NX bit on stack and heap.
    • Added {@code -z relro} and {@code -z now} to linker for hardening of internal data sections after linking to guard against security vulnerabilities caused by memory corruption. (more info: 1, 2)
    • These features can be disabled using the following options:
      1. Disable NX protection by setting the {@code --execstack} option for the assembler and {@code -z execstack} for the linker.
      2. Disable hardening of internal data by setting the {@code -z norelro} and {@code -z lazy} options for the linker.
      3. Disable these protections in the NDK {@code jni/Android.mk} by setting the following options: 
        LOCAL_DISABLE_NO_EXECUTE=true  # disable "--noexecstack" and "-z noexecstack"
DISABLE_RELRO=true             # disable "-z relro" and "-z now"

      See {@code docs/ANDROID-MK.html} for more details.

  • Added branding for Android executables with the {@code .note.ABI-tag} section (in {@code crtbegin_static/dynamic.o}) so that debugging tools can act accordingly. The structure member and values are defined as follows:

    static const struct {
  int32_t namesz;  /* = 4,  sizeof ("GNU") */
  int32_t descsz;  /* = 6 * sizeof(int32_t) */
  int32_t type;    /* = 1 */
  char  name[sizeof "GNU"];  /* = "GNU" */
  int32_t os;      /* = 0 */
  int32_t major;   /* = 2 */
  int32_t minor;   /* = 6 */
  int32_t teeny;   /* = 15 */
  int32_t os_variant;  /* = 1 */
  int32_t android_api; /* = 3, 4, 5, 8, 9, 14 */
}
Other bug fixes:
  • Fixed {@code mips-linux-gnu} relocation truncated to fit {@code R_MIPS_TLS_LDM} issue. (more info)
  • Fixed {@code ld} tool segfaults when using {@code --gc-sections}. (more info)
  • Fixed MIPS {@code GOT_PAGE} counting issue. (more info)
  • Fixed follow warning symbol link for {@code mips_elf_count_got_symbols}.
  • Fixed follow warning symbol link for {@code mips_elf_allocate_lazy_stub}.
  • Moved MIPS {@code .dynamic} to the data segment, so that it is writable.
  • Replaced hard-coded values for symbols with correct segment sizes for MIPS.
  • Removed the {@code -mno-shared} option from the defaults in the MIPS toolchain. The default for Android toolchain is {@code -fPIC} (or {@code -fpic} if supported). If you do not explicitly specify {@code -mshared}, {@code -fpic}, {@code -fPIC}, {@code -fpie}, or {@code -fPIE}, the MIPS compiler adds {@code -mno-shared} that turns off PIC. Fixed compiler not to add {@code -mno-shared} in this case.
  • Fixed wrong package names in samples {@code hello-jni} and {@code two-libs} so that the {@code tests} project underneath it can compile.
Other Changes:
  • Changed locations of binaries:
    • Moved {@code gdbserver} from {@code toolchain/<arch-os-ver>/prebuilt/gdbserver} to {@code prebuilt/android-<arch>/gdbserver/gdbserver}.
    • Renamed x86 toolchain prefix from {@code i686-android-linux-} to {@code i686-linux-android-}.
    • Moved {@code sources/cxx-stl/gnu-libstdc++/include} and {@code lib} to {@code sources/cxx-stl/gnu-libstdc++/4.6} when compiled with GCC 4.6, or {@code sources/cxx-stl/gnu-libstdc++/4.4.3} when compiled with GCC 4.4.3.
    • Moved {@code libbfd.a} and {@code libintl.a} from {@code lib/} to {@code lib32/}.
  • Added and improved various scripts in the rebuild and test NDK toolchain:
    • Added {@code build-mingw64-toolchain.sh} to generate a new Linux-hosted toolchain that generates Win32 and Win64 executables.
    • Improved speed of {@code download-toolchain-sources.sh} by using the {@code clone} command and only using {@code checkout} for the directories that are needed to build the NDK toolchain binaries.
    • Added {@code build-host-gcc.sh} and {@code build-host-gdb.sh} scripts.
    • Added {@code tests/check-release.sh} to check the content of a given NDK installation directory, or an existing NDK package.
    • Rewrote the {@code tests/standalone/run.sh} standalone tests .
  • Removed {@code if_dl.h} header from all platforms and architectures. The {@code AF_LINK} and {@code sockaddr_dl} elements it describes are specific to BSD (i.e., they don't exist in Linux).
Android NDK, Revision 8 (May 2012)

This release of the NDK includes support for MIPS ABI and a few additional fixes.

New features:
  • Added support for the MIPS ABI, which allows you to generate machine code that runs on compatible MIPS-based Android devices. Major features for MIPS include MIPS-specific toolchains, system headers, libraries and debugging support. For more details regarding MIPS support, see {@code docs/CPU-MIPS.html} in the NDK package.

    By default, code is generated for ARM-based devices. You can add {@code mips} to your {@code APP_ABI} definition in your {@code Application.mk} file to build for MIPS platforms. For example, the following line instructs {@code ndk-build} to build your code for three distinct ABIs:

    APP_ABI := armeabi armeabi-v7a mips

    Unless you rely on architecture-specific assembly sources, such as ARM assembly code, you should not need to touch your {@code Android.mk} files to build MIPS machine code.

  • You can build a standalone MIPS toolchain using the {@code --arch=mips} option when calling make-standalone-toolchain.sh. See {@code docs/STANDALONE-TOOLCHAIN.html} for more details.

Note: To ensure that your applications are available to users only if their devices are capable of running them, Google Play filters applications based on the instruction set information included in your application ? no action is needed on your part to enable the filtering. Additionally, the Android system itself also checks your application at install time and allows the installation to continue only if the application provides a library that is compiled for the device's CPU architecture.

Important bug fixes:
  • Fixed a typo in GAbi++ implementation where the result of {@code dynamic_cast<D>(b)} of base class object {@code b} to derived class {@code D} is incorrectly adjusted in the opposite direction from the base class. (Issue 28721)
  • Fixed an issue in which {@code make-standalone-toolchain.sh} fails to copy {@code libsupc++.*}.
Other bug fixes:
  • Fixed {@code ndk-build.cmd} to ensure that {@code ndk-build.cmd} works correctly even if the user has redefined the {@code SHELL} environment variable, which may be changed when installing a variety of development tools in Windows environments.
Android NDK, Revision 7c (April 2012)

This release of the NDK includes an important fix for Tegra2-based devices, and a few additional fixes and improvements:

Important bug fixes:
  • Fixed GNU STL armeabi-v7a binaries to not crash on non-NEON devices. The files provided with NDK r7b were not configured properly, resulting in crashes on Tegra2-based devices and others when trying to use certain floating-point functions (e.g., {@code cosf}, {@code sinf}, {@code expf}).
Important changes:
  • Added support for custom output directories through the {@code NDK_OUT} environment variable. When defined, this variable is used to store all intermediate generated files, instead of {@code $PROJECT_PATH/obj}. The variable is also recognized by {@code ndk-gdb}.
  • Added support for building modules with hundreds or even thousands of source files by defining {@code LOCAL_SHORT_COMMANDS} to {@code true} in your {@code Android.mk}.

    This change forces the NDK build system to put most linker or archiver options into list files, as a work-around for command-line length limitations. See {@code docs/ANDROID-MK.html} for details.

Other bug fixes:
  • Fixed {@code android_getCpuCount()} implementation in the {@code cpufeatures} helper library. On certain devices, where cores are enabled dynamically by the system, the previous implementation would report the total number of active cores the first time the function was called, rather than the total number of physically available cores.
Android NDK, Revision 7b (February 2012)

This release of the NDK includes fixes for native Windows builds, Cygwin and many other improvements:

Important bug fixes:
  • Updated {@code sys/atomics.h} to avoid correctness issues on some multi-core ARM-based devices. Rebuild your unmodified sources with this version of the NDK and this problem should be completely eliminated. For more details, read {@code docs/ANDROID-ATOMICS.html}.
  • Reverted to {@code binutils} 2.19 to fix debugging issues that appeared in NDK r7 (which switched to {@code binutils} 2.20.1).
  • Fixed {@code ndk-build} on 32-bit Linux. A packaging error put a 64-bit version of the {@code awk} executable under {@code prebuilt/linux-x86/bin} in NDK r7.
  • Fixed native Windows build ({@code ndk-build.cmd}). Other build modes were not affected. The fixes include:
    • Removed an infinite loop / stack overflow bug that happened when trying to call {@code ndk-build.cmd} from a directory that was not the top of your project path (e.g., in any sub-directory of it).
    • Fixed a problem where the auto-generated dependency files were ignored. This meant that updating a header didn't trigger recompilation of sources that included it.
    • Fixed a problem where special characters in files or paths, other than spaces and quotes, were not correctly handled.
  • Fixed the standalone toolchain to generate proper binaries when using {@code -lstdc++} (i.e., linking against the GNU {@code libstdc++} C++ runtime). You should use {@code -lgnustl_shared} if you want to link against the shared library version or {@code -lstdc++} for the static version.

    See {@code docs/STANDALONE-TOOLCHAIN.html} for more details about this fix.

  • Fixed {@code gnustl_shared} on Cygwin. The linker complained that it couldn't find {@code libsupc++.a} even though the file was at the right location.
  • Fixed Cygwin C++ link when not using any specific C++ runtime through {@code APP_STL}.
Other changes:
  • When your application uses the GNU {@code libstdc++} runtime, the compiler will no longer forcibly enable exceptions and RTTI. This change results in smaller code.

    If you need these features, you must do one of the following:

    • Enable exceptions and/or RTTI explicitly in your modules or {@code Application.mk}. (recommended)
    • Define {@code APP_GNUSTL_FORCE_CPP_FEATURES} to {@code 'exceptions'}, {@code 'rtti'} or both in your {@code Application.mk}. See {@code docs/APPLICATION-MK.html} for more details.
  • {@code ndk-gdb} now works properly when your application has private services running in independent processes. It debugs the main application process, instead of the first process listed by {@code ps}, which is usually a service process.
  • Fixed a rare bug where NDK r7 would fail to honor the {@code LOCAL_ARM_MODE} value and always compile certain source files (but not all) to 32-bit instructions.
  • {@code stlport}: Refresh the sources to match the Android platform version. This update fixes a few minor bugs:
    • Fixed instantiation of an incomplete type
    • Fixed minor "==" versus "=" typo
    • Used {@code memmove} instead of {@code memcpy} in {@code string::assign}
    • Added better handling of {@code IsNANorINF}, {@code IsINF}, {@code IsNegNAN}, etc.

    For complete details, see the commit log.

  • {@code stlport}: Removed 5 unnecessary static initializers from the library.
  • The GNU libstdc++ libraries for armeabi-v7a were mistakenly compiled for armeabi instead. This change had no impact on correctness, but using the right ABI should provide slightly better performance.
  • The {@code cpu-features} helper library was updated to report three optional x86 CPU features ({@code SSSE3}, {@code MOVBE} and {@code POPCNT}). See {@code docs/CPU-FEATURES.html} for more details.
  • {@code docs/NDK-BUILD.html} was updated to mention {@code NDK_APPLICATION_MK} instead of {@code NDK_APP_APPLICATION_MK} to select a custom {@code Application.mk} file.
  • Cygwin: {@code ndk-build} no longer creates an empty "NUL" file in the current directory when invoked.
  • Cygwin: Added better automatic dependency detection. In the previous version, it didn't work properly in the following cases:
    • When the Cygwin drive prefix was not {@code /cygdrive}.
    • When using drive-less mounts, for example, when Cygwin would translate {@code /home} to {@code \\server\subdir} instead of {@code C:\Some\Dir}.
  • Cygwin: {@code ndk-build} does not try to use the native Windows tools under {@code $NDK/prebuilt/windows/bin} with certain versions of Cygwin and/or GNU Make.
Android NDK, Revision 7 (November 2011)

This release of the NDK includes new features to support the Android 4.0 platform as well as many other additions and improvements:

New features
  • Added official NDK APIs for Android 4.0 (API level 14), which adds the following native features to the platform:
    • Added native multimedia API based on the Khronos Group OpenMAX AL? 1.0.1 standard. The new <OMXAL/OpenMAXAL.h> and <OMXAL/OpenMAXAL_Android.h> headers allow applications targeting API level 14 to perform multimedia output directly from native code by using a new Android-specific buffer queue interface. For more details, see docs/openmaxal/index.html and http://www.khronos.org/openmax/.
    • Updated the native audio API based on the Khronos Group OpenSL ES 1.0.1? standard. With API Level 14, you can now decode compressed audio (e.g. MP3, AAC, Vorbis) to PCM. For more details, see docs/opensles/index.html and http://www.khronos.org/opensles/.
  • Added CCache support. To speed up large rebuilds, define the NDK_CCACHE environment variable to ccache (or the path to your ccache binary). When declared, the NDK build system automatically uses CCache when compiling any source file. For example: 
    export NDK_CCACHE=ccache

    Note: CCache is not included in the NDK release so you must have it installed prior to using it. For more information about CCache, see http://ccache.samba.org.

  • Added support for setting APP_ABI to all to indicate that you want to build your NDK modules for all the ABIs supported by your given NDK release. This means that either one of the following two lines in your Application.mk are equivalent with this release: 
    APP_ABI := all
APP_ABI := armeabi armeabi-v7a x86

    This also works if you define APP_ABI when calling ndk-build from the command-line, which is a quick way to check that your project builds for all supported ABIs without changing the project's Application.mk file. For example:

    ndk-build APP_ABI=all
  • Added a LOCAL_CPP_FEATURES variable in Android.mk that allows you to declare which C++ features (RTTI or Exceptions) your module uses. This ensures that the final linking works correctly if you have prebuilt modules that depend on these features. See docs/ANDROID-MK.html and docs/CPLUSPLUS-SUPPORT.html for more details.
  • Shortened paths to source and object files that are used in build commands. When invoking $NDK/ndk-build from your project path, the paths to the source, object, and binary files that are passed to the build commands are significantly shorter now, because they are passed relative to the current directory. This is useful when building projects with a lot of source files, to avoid limits on the maximum command line length supported by your host operating system. The behavior is unchanged if you invoke ndk-build from a sub-directory of your project tree, or if you define NDK_PROJECT_PATH to point to a specific directory.
Experimental features
You can now build your NDK source files on Windows without Cygwin by calling the ndk-build.cmd script from the command line from your project path. The script takes exactly the same arguments as the original ndk-build script. The Windows NDK package comes with its own prebuilt binaries for GNU Make, Awk and other tools required by the build. You should not need to install anything else to get a working build system.

Important: ndk-gdb does not work on Windows, so you still need Cygwin to debug.

This feature is still experimental, so feel free to try it and report issues on the public bug database or public forum. All samples and unit tests shipped with the NDK succesfully compile with this feature.

Important bug fixes
  • Imported shared libraries are now installed by default to the target installation location (libs/<abi>) if APP_MODULES is not defined in your Application.mk. For example, if a top-level module foo imports a module bar, then both libfoo.so and libbar.so are copied to the install location. Previously, only libfoo.so was copied, unless you listed bar in your APP_MODULES too. If you define APP_MODULES explicitly, the behavior is unchanged.
  • ndk-gdb now works correctly for activities with multiple categories in their MAIN intent filters.
  • Static library imports are now properly transitive. For example, if a top-level module foo imports static library bar that imports static library zoo, the libfoo.so will now be linked against both libbar.a and libzoo.a.
Other changes
  • docs/NATIVE-ACTIVITY.HTML: Fixed typo. The minimum API level should be 9, not 8 for native activities.
  • docs/STABLE-APIS.html: Added missing documentation listing EGL as a supported stable API, starting from API level 9.
  • download-toolchain-sources.sh: Updated to download the toolchain sources from android.googlesource.com, which is the new location for the AOSP servers.
  • Added a new C++ support runtime named gabi++. More details about it are available in the updated docs/CPLUSPLUS-SUPPORT.html.
  • Added a new C++ support runtime named gnustl_shared that corresponds to the shared library version of GNU libstdc++ v3 (GPLv3 license). See more info at docs/CPLUSPLUS-SUPPORT.html
  • Added support for RTTI in the STLport C++ runtimes (no support for exceptions).
  • Added support for multiple file extensions in LOCAL_CPP_EXTENSION. For example, to compile both foo.cpp and bar.cxx as C++ sources, declare the following: 
    LOCAL_CPP_EXTENSION := .cpp .cxx
  • Removed many unwanted exported symbols from the link-time shared system libraries provided by the NDK. This ensures that code generated with the standalone toolchain doesn't risk to accidentally depend on a non-stable ABI symbol (e.g. any libgcc.a symbol that changes each time the toolchain used to build the platform is changed)
  • Refreshed the EGL and OpenGLES Khronos headers to support more extensions. Note that this does not change the NDK ABIs for the corresponding libraries, because each extension must be probed at runtime by the client application.

    The extensions that are available depend on your actual device and GPU drivers, not the platform version the device runs on. The header changes simply add new constants and types to make it easier to use the extensions when they have been probed with eglGetProcAddress() or glGetProcAddress(). The following list describes the newly supported extensions:

    GLES 1.x
    • GL_OES_vertex_array_object
    • GL_OES_EGL_image_external
    • GL_APPLE_texture_2D_limited_npot
    • GL_EXT_blend_minmax
    • GL_EXT_discard_framebuffer
    • GL_EXT_multi_draw_arrays
    • GL_EXT_read_format_bgra
    • GL_EXT_texture_filter_anisotropic
    • GL_EXT_texture_format_BGRA8888
    • GL_EXT_texture_lod_bias
    • GL_IMG_read_format
    • GL_IMG_texture_compression_pvrtc
    • GL_IMG_texture_env_enhanced_fixed_function
    • GL_IMG_user_clip_plane
    • GL_IMG_multisampled_render_to_texture
    • GL_NV_fence
    • GL_QCOM_driver_control
    • GL_QCOM_extended_get
    • GL_QCOM_extended_get2
    • GL_QCOM_perfmon_global_mode
    • GL_QCOM_writeonly_rendering
    • GL_QCOM_tiled_rendering
    GLES 2.0
    • GL_OES_element_index_uint
    • GL_OES_get_program_binary
    • GL_OES_mapbuffer
    • GL_OES_packed_depth_stencil
    • GL_OES_texture_3D
    • GL_OES_texture_float
    • GL_OES_texture_float_linear
    • GL_OES_texture_half_float_linear
    • GL_OES_texture_npot
    • GL_OES_vertex_array_object
    • GL_OES_EGL_image_external
    • GL_AMD_program_binary_Z400
    • GL_EXT_blend_minmax
    • GL_EXT_discard_framebuffer
    • GL_EXT_multi_draw_arrays
    • GL_EXT_read_format_bgra
    • GL_EXT_texture_format_BGRA8888
    • GL_EXT_texture_compression_dxt1
    • GL_IMG_program_binary
    • GL_IMG_read_format
    • GL_IMG_shader_binary
    • GL_IMG_texture_compression_pvrtc
    • GL_IMG_multisampled_render_to_texture
    • GL_NV_coverage_sample
    • GL_NV_depth_nonlinear
    • GL_QCOM_extended_get
    • GL_QCOM_extended_get2
    • GL_QCOM_writeonly_rendering
    • GL_QCOM_tiled_rendering
    EGL
    • EGL_ANDROID_recordable
    • EGL_NV_system_time
Android NDK, Revision 6b (August 2011)

This release of the NDK does not include any new features compared to r6. The r6b release addresses the following issues in the r6 release:

Important bug fixes
  • Fixed the build when APP_ABI="armeabi x86" is used for multi-architecture builds.
  • Fixed the location of prebuilt STLport binaries in the NDK release package. A bug in the packaging script placed them in the wrong location.
  • Fixed atexit() usage in shared libraries with the x86standalone toolchain.
  • Fixed make-standalone-toolchain.sh --arch=x86. It used to fail to copy the proper GNU libstdc++ binaries to the right location.
  • Fixed the standalone toolchain linker warnings about missing the definition and size for the __dso_handle symbol (ARM only).
  • Fixed the inclusion order of $(SYSROOT)/usr/include for x86 builds. See the bug for more information.
  • Fixed the definitions of ptrdiff_t and size_t in x86-specific systems when they are used with the x86 standalone toolchain.
Android NDK, Revision 6 (July 2011)

This release of the NDK includes support for the x86 ABI and other minor changes. For detailed information describing the changes in this release, read the CHANGES.HTML document included in the NDK package.

General notes:
  • Adds support for the x86 ABI, which allows you to generate machine code that runs on compatible x86-based Android devices. Major features for x86 include x86-specific toolchains, system headers, libraries and debugging support. For all of the details regarding x86 support, see docs/CPU-X86.html in the NDK package.

    By default, code is generated for ARM-based devices, but you can add x86 to your APP_ABI definition in your Application.mk file to build for x86 platforms. For example, the following line instructs ndk-build to build your code for three distinct ABIs:

    APP_ABI := armeabi armeabi-v7a x86

    Unless you rely on ARM-based assembly sources, you shouldn't need to touch your Android.mk files to build x86 machine code.

  • You can build a standalone x86 toolchain using the --toolchain=x86-4.4.3 option when calling make-standalone-toolchain.sh. See docs/STANDALONE-TOOLCHAIN.html for more details.
  • The new ndk-stack tool lets you translate stack traces in logcat that are generated by native code. The tool translates instruction addresses into a readable format that contains things such as the function, source file, and line number corresponding to each stack frame. For more information and a usage example, see docs/NDK-STACK.html.
Other changes:
arm-eabi-4.4.0, which had been deprecated since NDK r5, has been removed from the NDK distribution.
Android NDK, Revision 5c (June 2011)

This release of the NDK does not include any new features compared to r5b. The r5c release addresses the following problems in the r5b release:

Important bug fixes:
  • ndk-build: Fixed a rare bug that appeared when trying to perform parallel builds of debuggable projects.
  • Fixed a typo that prevented LOCAL_WHOLE_STATIC_LIBRARIES to work correctly with the new toolchain and added documentation for this in docs/ANDROID-MK.html.
  • Fixed a bug where code linked against gnustl_static crashed when run on platform releases older than API level 8 (Android 2.2).
  • ndk-gdb: Fixed a bug that caused a segmentation fault when debugging Android 3.0 or newer devices.
  • <android/input.h>: Two functions that were introduced in API level 9 (Android 2.3) were incorrect and are fixed. While this breaks the source API, the binary interface to the system is unchanged. The incorrect functions were missing a history_index parameter, and the correct definitions are shown below: 
    float AMotionEvent_getHistoricalRawX(const AInputEvent* motion_event,
                                           size_t pointer_index,
                                           size_t history_index);

float AMotionEvent_getHistoricalRawY(const AInputEvent* motion_event,
                                           size_t pointer_index,
                                           size_t history_index);
  • Updated the C library ARM binary for API level 9 (Android 2.3) to correctly expose at link time new functions that were added in that API level (for example, pthread_rwlock_init).
Minor improvements and fixes:
  • Object files are now always linked in the order they appear in LOCAL_SRC_FILES. This was not the case previously because the files were grouped by source extensions instead.
  • When import-module fails, it now prints the list of directories that were searched. This is useful to check that the NDK_MODULE_PATH definition used by the build system is correct.
  • When import-module succeeds, it now prints the directory where the module was found to the log (visible with NDK_LOG=1).
  • Increased the build speed of debuggable applications when there is a very large number of include directories in the project.
  • ndk-gdb: Better detection of adb shell failures and improved error messages.
  • <pthread.h>: Fixed the definition of PTHREAD_RWLOCK_INITIALIZER for API level 9 (Android 2.3) and higher.
  • Fixed an issue where a module could import itself, resulting in an infinite loop in GNU Make.
  • Fixed a bug that caused the build to fail if LOCAL_ARM_NEON was set to true (typo in build/core/build-binary.mk).
  • Fixed a bug that prevented the compilation of .s assembly files (.S files were okay).
Android NDK, Revision 5b (January 2011)

This release of the NDK does not include any new features compared to r5. The r5b release addresses the following problems in the r5 release:

Android NDK, Revision 5 (December 2010)

This release of the NDK includes many new APIs, most of which are introduced to support the development of games and similar applications that make extensive use of native code. Using the APIs, developers have direct native access to events, audio, graphics and window management, assets, and storage. Developers can also implement the Android application lifecycle in native code with help from the new {@link android.app.NativeActivity} class. For detailed information describing the changes in this release, read the CHANGES.HTML document included in the downloaded NDK package.

General notes:
  • Adds support for native activities, which allows you to implement the Android application lifecycle in native code.
  • Adds native support for the following:
    • Input subsystem (such as the keyboard and touch screen)
    • Access to sensor data (accelerometer, compass, gyroscope, etc).
    • Event loop APIs to wait for things such as input and sensor events.
    • Window and surface subsystem
    • Audio APIs based on the OpenSL ES standard that support playback and recording as well as control over platform audio effects
    • Access to assets packaged in an .apk file.
  • Includes a new toolchain (based on GCC 4.4.3), which generates better code, and can also now be used as a standalone cross-compiler, for people who want to build their stuff with ./configure && make. See docs/STANDALONE-TOOLCHAIN.html for the details. The binaries for GCC 4.4.0 are still provided, but the 4.2.1 binaries were removed.
  • Adds support for prebuilt static and shared libraries (docs/PREBUILTS.html) and module exports and imports to make sharing and reuse of third-party modules much easier (docs/IMPORT-MODULE.html explains why).
  • Provides a default C++ STL implementation (based on STLport) as a helper module. It can be used either as a static or shared library (details and usage examples are in sources/android/stlport/README). Prebuilt binaries for STLport (static or shared) and GNU libstdc++ (static only) are also provided if you choose to compile against those libraries instead of the default C++ STL implementation. C++ Exceptions and RTTI are not supported in the default STL implementation. For more information, see docs/CPLUSPLUS-SUPPORT.HTML.
  • Includes improvements to the cpufeatures helper library that improves reporting of the CPU type (some devices previously reported ARMv7 CPU when the device really was an ARMv6). We recommend developers that use this library to rebuild their applications then upload to Google Play to benefit from the improvements.
  • Adds an EGL library that lets you create and manage OpenGL ES textures and services.
  • Adds new sample applications, native-plasma and native-activity, to demonstrate how to write a native activity.
  • Includes many bugfixes and other small improvements; see docs/CHANGES.html for a more detailed list of changes.
Android NDK, Revision 4b (June 2010)
NDK r4b notes:

Includes fixes for several issues in the NDK build and debugging scripts — if you are using NDK r4, we recommend downloading the NDK r4b build. For detailed information describing the changes in this release, read the CHANGES.TXT document included in the downloaded NDK package.

General notes:
  • Provides a simplified build system through the new ndk-build build command.
  • Adds support for easy native debugging of generated machine code on production devices through the new ndk-gdb command.
  • Adds a new Android-specific ABI for ARM-based CPU architectures, armeabi-v7a. The new ABI extends the existing armeabi ABI to include these CPU instruction set extensions:
    • Thumb-2 instructions
    • VFP hardware FPU instructions (VFPv3-D16)
    • Optional support for ARM Advanced SIMD (NEON) GCC intrinsics and VFPv3-D32. Supported by devices such as Verizon Droid by Motorola, Google Nexus One, and others.
  • Adds a new cpufeatures static library (with sources) that lets your app detect the host device's CPU features at runtime. Specifically, applications can check for ARMv7-A support, as well as VFPv3-D32 and NEON support, then provide separate code paths as needed.
  • Adds a sample application, hello-neon, that illustrates how to use the cpufeatures library to check CPU features and then provide an optimized code path using NEON instrinsics, if supported by the CPU.
  • Lets you generate machine code for either or both of the instruction sets supported by the NDK. For example, you can build for both ARMv5 and ARMv7-A architectures at the same time and have everything stored to your application's final .apk.
  • To ensure that your applications are available to users only if their devices are capable of running them, Google Play now filters applications based on the instruction set information included in your application — no action is needed on your part to enable the filtering. Additionally, the Android system itself also checks your application at install time and allows the installation to continue only if the application provides a library that is compiled for the device's CPU architecture.
  • Adds support for Android 2.2, including a new stable API for accessing the pixel buffers of {@link android.graphics.Bitmap} objects from native code.
Android NDK, Revision 3 (March 2010)
General notes:
  • Adds OpenGL ES 2.0 native library support.
  • Adds a sample application,hello-gl2, that illustrates the use of OpenGL ES 2.0 vertex and fragment shaders.
  • The toolchain binaries have been refreshed for this release with GCC 4.4.0, which should generate slightly more compact and efficient machine code than the previous one (4.2.1). The NDK also still provides the 4.2.1 binaries, which you can optionally use to build your machine code.
Android NDK, Revision 2 (September 2009)

Originally released as "Android 1.6 NDK, Release 1".

General notes:
  • Adds OpenGL ES 1.1 native library support.
  • Adds a sample application, san-angeles, that renders 3D graphics through the native OpenGL ES APIs, while managing activity lifecycle with a {@link android.opengl.GLSurfaceView} object.
Android NDK, Revision 1 (June 2009)

Originally released as "Android 1.5 NDK, Release 1".

General notes:
  • Includes compiler support (GCC) for ARMv5TE instructions, including Thumb-1 instructions.
  • Includes system headers for stable native APIs, documentation, and sample applications.

System and Software Requirements

The sections below describe the system and software requirements for using the Android NDK, as well as platform compatibility considerations that affect appplications using libraries produced with the NDK.

The Android SDK

Supported operating systems

Required development tools

Android platform compatibility

Installing the NDK

Installing the NDK on your development computer is straightforward and involves extracting the NDK from its download package.

Before you get started make sure that you have downloaded the latest Android SDK and upgraded your applications and environment as needed. The NDK is compatible with older platform versions but not older versions of the SDK tools. Also, take a moment to review the System and Software Requirements for the NDK, if you haven't already.

To install the NDK, follow these steps:

  1. From the table at the top of this page, select the NDK package that is appropriate for your development computer and download the package.
  2. Uncompress the NDK download package using tools available on your computer. When uncompressed, the NDK files are contained in a directory called android-ndk-<version>. You can rename the NDK directory if necessary and you can move it to any location on your computer. This documentation refers to the NDK directory as <ndk>.

You are now ready to start working with the NDK.

Getting Started with the NDK

Once you've installed the NDK successfully, take a few minutes to read the documentation included in the NDK. You can find the documentation in the <ndk>/docs/ directory. In particular, please read the OVERVIEW.HTML document completely, so that you understand the intent of the NDK and how to use it.

If you used a previous version of the NDK, take a moment to review the list of NDK changes in the CHANGES.HTML document.

Here's the general outline of how you work with the NDK tools:

  1. Place your native sources under <project>/jni/...
  2. Create <project>/jni/Android.mk to describe your native sources to the NDK build system
  3. Optional: Create <project>/jni/Application.mk.
  4. Build your native code by running the 'ndk-build' script from your project's directory. It is located in the top-level NDK directory: 
    cd <project>
<ndk>/ndk-build

    The build tools copy the stripped, shared libraries needed by your application to the proper location in the application's project directory.

  5. Finally, compile your application using the SDK tools in the usual way. The SDK build tools will package the shared libraries in the application's deployable .apk file.

For complete information on all of the steps listed above, please see the documentation included with the NDK package.

Using the NDK

The Android framework provides two ways to use native code:

Contents of the NDK

The NDK contains the APIs, documentation, and sample applications that help you write your native code. Specifically:

The latest release of the NDK supports the following instruction sets:

ARMv5TE machine code will run on all ARM-based Android devices. ARMv7-A will run only on devices such as the Verizon Droid or Google Nexus One that have a compatible CPU. The main difference between the two instruction sets is that ARMv7-A supports hardware FPU, Thumb-2, and NEON instructions. You can target either or both of the instruction sets — ARMv5TE is the default, but switching to ARMv7-A is as easy as adding a single line to the application's Application.mk file, without needing to change anything else in the file. You can also build for both architectures at the same time and have everything stored in the final .apk. Complete information is provided in the CPU-ARCH-ABIS.HTML in the NDK package.

The NDK provides stable headers for libc (the C library), libm (the Math library), OpenGL ES (3D graphics library), the JNI interface, and other libraries, as listed in the Development tools section.

Development tools

The NDK includes a set of cross-toolchains (compilers, linkers, etc..) that can generate native ARM binaries on Linux, OS X, and Windows (with Cygwin) platforms.

It provides a set of system headers for stable native APIs that are guaranteed to be supported in all later releases of the platform:

The NDK also provides a build system that lets you work efficiently with your sources, without having to handle the toolchain/platform/CPU/ABI details. You create very short build files to describe which sources to compile and which Android application will use them — the build system compiles the sources and places the shared libraries directly in your application project.

Important: With the exception of the libraries listed above, native system libraries in the Android platform are not stable and may change in future platform versions. Your applications should only make use of the stable native system libraries provided in this NDK.

Documentation

The NDK package includes a set of documentation that describes the capabilities of the NDK and how to use it to create shared libraries for your Android applications. In this release, the documentation is provided only in the downloadable NDK package. You can find the documentation in the <ndk>/docs/ directory. Included are these files (partial listing):

Additionally, the package includes detailed information about the "bionic" C library provided with the Android platform that you should be aware of, if you are developing using the NDK. You can find the documentation in the <ndk>/docs/system/libc/ directory:

Sample apps

The NDK includes sample applications that illustrate how to use native code in your Android applications:

For each sample, the NDK includes the corresponding C source code and the necessary Android.mk and Application.mk files. There are located under <ndk>/samples/<name>/ and their source code can be found under <ndk>/samples/<name>/jni/.

You can build the shared libraries for the sample apps by going into <ndk>/samples/<name>/ then calling the ndk-build command. The generated shared libraries will be located under <ndk>/samples/<name>/libs/armeabi/ for (ARMv5TE machine code) and/or <ndk>/samples/<name>/libs/armeabi-v7a/ for (ARMv7 machine code).

Next, build the sample Android applications that use the shared libraries:

For more information about developing with the Android SDK tools and what you need to do to create, build, and run your applications, see the Overview section for developing on Android.

Exploring the hello-jni Sample

The hello-jni sample is a simple demonstration on how to use JNI from an Android application. The HelloJni activity receives a string from a simple C function and displays it in a TextView.

The main components of the sample include:

  1. Create a new project in Eclipse from the existing sample source or use the android tool to update the project so it generates a build.xml file that you can use to build the sample.
  2. Compile the native code using the ndk-build command. 
    cd <ndk-root>/samples/hello-jni
<ndk_root>/ndk-build
  3. Build and install the application as you would a normal Android application. If you are using Eclipse, run the application to build and install it on a device. If you are using Ant, run the following commands from the project directory: 
    ant debug
adb install bin/HelloJni-debug.apk

When you run the application on the device, the string Hello JNI should appear on your device. You can explore the rest of the samples that are located in the <ndk-root>/samples directory for more examples on how to use the JNI.

Exploring the native-activity Sample Application

The native-activity sample provided with the Android NDK demonstrates how to use the android_native_app_glue static library. This static library makes creating a native activity easier by providing you with an implementation that handles your callbacks in another thread, so you do not have to worry about them blocking your main UI thread. The main parts of the sample are described below:

To build this sample application:

  1. Create a new project in Eclipse from the existing sample source or use the android tool to update the project so it generates a build.xml file that you can use to build the sample.
  2. Compile the native code using the ndk-build command. 
    cd <ndk-root>/platforms/samples/android-9/samples/native-activity
<ndk_root>/ndk-build
  3. Build and install the application as you would a normal Android application. If you are using Eclipse, run the application to build and install it on a device. If you are using Ant, run the following commands in the project directory, then run the application on the device: 
    ant debug
adb install bin/NativeActivity-debug.apk