1<html><body><pre>Android NDK Stable APIs: 2======================== 3 4This is the list of stable APIs/ABIs exposed by the Android NDK. 5 6I. Purpose: 7----------- 8 9Each API corresponds to a set of headers files, and a shared library file 10that contains the corresponding implementation, and which must be linked 11against by your native code. 12 13For example, to use system library "Foo", you would include a header 14like <foo.h> in your code, then tell the build system that your native 15module needs to link to /system/lib/libfoo.so at load-time by adding 16the following line to your Android.mk file: 17 18 LOCAL_LDLIBS := -lfoo 19 20Note that the build system automatically links the C library, the Math 21library and the C++ support library to your native code, there is no 22need to list them in a LOCAL_LDLIBS line. 23 24There are several "API Levels" defined. Each API level corresponds to 25a given Android system platform release. The following levels are 26currently supported: 27 28 android-3 -> Official Android 1.5 system images 29 android-4 -> Official Android 1.6 system images 30 android-5 -> Official Android 2.0 system images 31 android-6 -> Official Android 2.0.1 system images 32 android-7 -> Official Android 2.1 system images 33 android-8 -> Official Android 2.2 system images 34 android-9 -> Official Android 2.3 system images 35 36Note that android-6 and android-7 are the same as android-5 for the NDK, 37i.e. they provide exactly the same native ABIs! 38 39IMPORTANT: 40 The headers corresponding to a given API level are now located 41 under $NDK/platforms/android-<level>/arch-arm/usr/include 42 43 44II. Android-3 Stable Native APIs: 45--------------------------------- 46 47All the APIs listed below are available for developing native code that 48runs on Android 1.5 system images and above. 49 50The C Library: 51-------------- 52 53The C library headers, as they are defined on Android 1.5 are available 54through their standard names (<stdlib.h>, <stdio.h>, etc...). If one header 55is not there at build time, it's because its implementation is not available 56on a 1.5 system image. 57 58The build system automatically links your native modules to the C library, 59you don't need to add it to LOCAL_LDLIBS. 60 61Note that the Android C library includes support for pthread (<pthread.h>), 62so "LOCAL_LIBS := -lpthread" is not needed. The same is true for real-time 63extensions (-lrt on typical Linux distributions). 64 65 66** VERY IMPORTANT NOTE: ****************************************************** 67* 68* The kernel-specific headers in <linux/...> and <asm/...> are not considered 69* stable at this point. Avoid including them directly because some of them 70* are likely to change in future releases of the platform. This is especially 71* true for anything related to specific hardware definitions. 72* 73****************************************************************************** 74 75 76The Math Library: 77----------------- 78 79<math.h> is available, and the math library is automatically linked to your 80native modules at build time, so there is no need to list "-lm" through 81LOCAL_LDLIBS. 82 83 84 85C++ Library: 86------------ 87 88An *extremely* minimal C++ support API is available. For Android 1.5, this is 89currently limited to the following headers: 90 91 <cstddef> 92 <new> 93 <utility> 94 <stl_pair.h> 95 96They may not contain all definitions required by the standard. Notably, 97support for C++ exceptions and RTTI is not available with Android 1.5 system 98images. 99 100The C++ support library (-lstdc++) is automatically linked to your native 101modules too, so there is no need to list it through LOCAL_LDLIBS 102 103 104 105Android-specific Log Support: 106----------------------------- 107 108<android/log.h> contains various definitions that can be used to send log 109messages to the kernel from your native code. Please have a look at its 110content in (build/platforms/android-3/common/include/android/log.h), which 111contain many informative comments on how to use it. 112 113You should be able to write helpful wrapper macros for your own usage to 114access this facility. 115 116If you use it, your native module should link to /system/lib/liblog.so with: 117 118 LOCAL_LDLIBS := -llog 119 120 121ZLib Compression Library: 122------------------------- 123 124<zlib.h> and <zconf.h> are available and can be used to use the ZLib 125compression library. Documentation for it is at the ZLib page: 126 127 http://www.zlib.net/manual.html 128 129If you use it, your native module should link to /system/lib/libz.so with: 130 131 LOCAL_LDLIBS := -lz 132 133 134Dynamic Linker Library: 135----------------------- 136 137<dlfcn.h> is available and can be used to use the dlopen()/dlsym()/dlclose() 138functions provided by the Android dynamic linker. You will need to link 139against /system/lib/libdl.so with: 140 141 LOCAL_LDLIBS := -ldl 142 143 144III. Android-4 Stable Native APIs: 145---------------------------------- 146 147All the APIs listed below are available for developing native code that runs 148on Android 1.6 system images and above, 149 150 151The OpenGL ES 1.x Library: 152-------------------------- 153 154The standard OpenGL ES headers <GLES/gl.h> and <GLES/glext.h> contain the 155declarations needed to perform OpenGL ES 1.x rendering calls from native 156code. 157 158If you use them, your native module should link to /system/lib/libGLESv1_CM.so 159as in: 160 161 LOCAL_LDLIBS := -lGLESv1_CM 162 163 164The '1.x' here refers to both versions 1.0 and 1.1 of the OpenGL ES APIs. 165Please note that: 166 167 - OpenGL ES 1.0 is supported on *all* Android-based devices. 168 - OpenGL ES 1.1 is fully supported only on specific devices that 169 have the corresponding GPU. 170 171This is because Android comes with a 1.0-capable software renderer that can 172be used on GPU-less devices. 173 174Developers should query the OpenGL ES version string and extension string 175to know if the current device supports the features they need. See the 176description of glGetString() in the specification to see how to do that: 177 178 http://www.khronos.org/opengles/sdk/1.1/docs/man/glGetString.xml 179 180Additionally, developers must put a <uses-feature> tag in their manifest 181file to indicate which version of OpenGL ES their application requires. See 182the documentation linked below for details: 183 184 http://developer.android.com/guide/topics/manifest/uses-feature-element.html 185 186Please note that, at the moment, native headers and libraries for the EGL APIs 187are *not* available. EGL is used to perform surface creation and flipping 188(instead of rendering). The corresponding operations must be performed in your 189VM application instead, for example with a GLSurfaceView, as described here: 190 191http://android-developers.blogspot.com/2009/04/introducing-glsurfaceview.html 192 193The "san-angeles" sample application shows how you can do that, while 194rendering each frame in native code. This is a small Android port of the 195excellent "San Angeles Observation" demo program. For more information about 196it, see: 197 198 http://jet.ro/visuals/san-angeles-observation/ 199 200 201IV. Android-5 Stable Native APIs: 202---------------------------------- 203 204All the APIs listed below are available for developing native code that runs 205on Android 2.0 system images and above. 206 207 208The OpenGL ES 2.0 Library: 209-------------------------- 210 211The standard OpenGL ES 2.0 headers <GLES2/gl2.h> and <GLES2/gl2ext.h> contain the 212declarations needed to perform OpenGL ES 2.0 rendering calls from native code. 213This includes the ability to define and use vertex and fragment shaders using the 214GLSL language. 215 216If you use them, your native module should link to /system/lib/libGLESv2.so 217as in: 218 219 LOCAL_LDLIBS := -lGLESv2 220 221Not all devices support OpenGL ES 2.0, developers should thus query the 222implementation's version and extension strings, and put a <uses-feature> 223tag in their Android manifest. See Section III above for details. 224 225Please note that, at the moment, native headers and libraries for the EGL APIs 226are *not* available. EGL is used to perform surface creation and flipping 227(instead of rendering). The corresponding operations must be performed in your 228VM application instead, for example with a GLSurfaceView, as described here: 229 230http://android-developers.blogspot.com/2009/04/introducing-glsurfaceview.html 231 232The "hello-gl2" sample application demonstrate this. It is used to draw a very 233simple triangle with the help of a vertex and fragment shaders. 234 235IMPORTANT NOTE: 236 The Android emulator does not support OpenGL ES 2.0 hardware emulation 237 at this time. Running and testing code that uses this API requires a 238 real device with such capabilities. 239 240 241IV. Android-8 Stable Native APIs: 242---------------------------------- 243 244All the APIs listed below are available for developing native code that runs 245on Android 2.2 system images and above. 246 247 248The 'jnigraphics' Library: 249-------------------------- 250 251This is a tiny library that exposes a stable, C-based, interface that allows 252native code to reliably access the pixel buffers of Java bitmap objects. 253 254To use it, include the <android/bitmap.h> header in your source code, and 255and link to the jnigraphics library as in: 256 257 LOCAL_LDLIBS += -ljnigraphics 258 259For details, read the source header at the following location: 260 261 build/platforms/android-8/arch-arm/usr/include/android/bitmap.h 262 263Briefly, typical usage should look like: 264 265 1/ Use AndroidBitmap_getInfo() to retrieve information about a 266 given bitmap handle from JNI (e.g. its width/height/pixel format) 267 268 2/ Use AndroidBitmap_lockPixels() to lock the pixel buffer and 269 retrieve a pointer to it. This ensures the pixels will not move 270 until AndroidBitmap_unlockPixels() is called. 271 272 3/ Modify the pixel buffer, according to its pixel format, width, 273 stride, etc.., in native code. 274 275 4/ Call AndroidBitmap_unlockPixels() to unlock the buffer. 276 277 278V. Android-9 Stable Native APIs: 279-------------------------------- 280 281All the APIs listed below are available for developing native code that runs 282on Android > 2.2 system images and above. 283 284The OpenSL ES native audio Library: 285----------------------------------- 286 287Android native audio is based on Khronos Group OpenSL ES™ 1.0.1. 288 289The standard OpenSL ES headers <SLES/OpenSLES.h> and <SLES/OpenSLES_Platform.h> 290contain the declarations needed to perform audio input and output from the 291native side of Android. 292 293NOTE: Despite the fact that the current OpenSL ES specification uses 294 <OpenSLES.h> to include these headers, Khronos is currently modifying 295 the document to recommend <SLES/OpenSLES.h> instead, hence the later 296 approach was adopted for Android. 297 298This API level also provides Android-specific extensions, see the content 299of <SLES/OpenSLES_Android.h> and <SLES/OpenSLES_AndroidConfiguration.h> for 300details. 301 302The system library named "libOpenSLES.so" implements the public native audio 303functions. Use the following to link your modules against it: 304 305 LOCAL_LDLIBS += -lOpenSLES 306 307 308The Android native application APIs: 309------------------------------------ 310 311Starting from API level 9, it is possible to entirely write an Android 312application with native code (i.e. without any Java). That does not mean 313that your code does not run inside a VM though, and most of the features 314of the platform will still need to be accessed through JNI. 315 316For more information about this topic, please read the dedicated 317document named docs/NATIVE-ACTIVITY.html (TODO: WRITE DOC). 318 319The following headers correspond to these new native APIs (see comments 320inside them for more details): 321 322 <android/native_activity.h> 323 324 Activity lifecycle management (and general entry point) 325 326 <android/looper.h> 327 <android/input.h> 328 <android/keycodes.h> 329 <android/sensor.h> 330 331 To Listen to input events and sensors directly from native code. 332 333 <android/rect.h> 334 <android/window.h> 335 <android/native_window.h> 336 <android/native_window_jni.h> 337 338 Window management, including the ability to lock/unlock the pixel 339 buffer to draw directly into it. 340 341 <android/configuration.h> 342 <android/asset_manager.h> 343 <android/storage_manager.h> 344 <android/obb.h> 345 Direct (read-only) access to assets embedded in your .apk. or 346 the Opaque Binary Blob (OBB) files, a new feature of Android X.X 347 that allows one to distribute large amount of application data 348 outside of the .apk (useful for game assets, for example). 349 350All the corresponding functions are provided by the "libandroid.so" library 351version that comes with API level 9. To use it, use the following: 352 353 LOCAL_LDLIBS += -landroid 354</pre></body></html> 355