1 <html><body><pre>Application.mk file syntax specification 2 3 Introduction: 4 ------------- 5 6 This document describes the syntax of Application.mk build files 7 written to describe the native modules required by your Android 8 application. To understand what follows, it is assumed that you have 9 read the docs/OVERVIEW.html file that explains their role and 10 usage. 11 12 Readers of this document should have read docs/OVERVIEW.html and 13 docs/ANDROID-MK.html 14 15 16 Overview: 17 --------- 18 19 The purpose of Application.mk is to describe which native 20 'modules' (i.e. static/shared libraries) are needed by your 21 application. 22 23 An Application.mk file is usually placed under $PROJECT/jni/Application.mk, 24 where $PROJECT points to your application's project directory. 25 26 Another alternative is to place it under a sub-directory of the top-level 27 $NDK/apps directory, e.g.: 28 29 $NDK/apps/<myapp>/Application.mk 30 31 Where <myapp> is a short name used to describe your 'application' 32 to the NDK build system (this name doesn't go into your generated 33 shared libraries or your final packages). 34 35 The Application.mk is really a tiny GNU Makefile fragment that must 36 define a few variables: 37 38 APP_PROJECT_PATH 39 This variable should give the *absolute* path to your 40 Application's project root directory. This is used to copy/install 41 stripped versions of the generated JNI shared libraries to a 42 specific location known to the APK-generating tools. 43 44 Note that it is optional for $PROJECT/jni/Application.mk, but 45 *mandatory* for $NDK/apps/<myapp>/Application.mk 46 47 APP_MODULES 48 This variable is optional. If not defined, the NDK will build by 49 default _all_ the modules declared by your Android.mk, and any 50 sub-makefile it may include. 51 52 If APP_MODULES is defined, it must be a space-separated list of module 53 names as they appear in the LOCAL_MODULE definitions of Android.mk 54 files. Note that the NDK will compute module dependencies automatically. 55 56 NOTE: This variable's behaviour changed in NDK r4. Before that: 57 58 - the variable was mandatory in your Application.mk 59 - all required modules had to be listed explicitly. 60 61 APP_OPTIM 62 This optional variable can be defined to either 'release' or 63 'debug'. This is used to alter the optimization level when 64 building your application's modules. 65 66 A 'release' mode is the default, and will generate highly 67 optimized binaries. The 'debug' mode will generate un-optimized 68 binaries which are much easier to debug. 69 70 Note that if your application is debuggable (i.e. if your manifest 71 sets the android:debuggable attribute to "true" in its <application> 72 tag), the default will be 'debug' instead of 'release'. This can 73 be overridden by setting APP_OPTIM to 'release'. 74 75 Note that it is possible to debug both 'release' and 'debug' 76 binaries, but the 'release' builds tend to provide less information 77 during debugging sessions: some variables are optimized out and 78 can't be inspected, code re-ordering can make stepping through 79 the code difficult, stack traces may not be reliable, etc... 80 81 APP_CFLAGS 82 A set of C compiler flags passed when compiling any C or C++ source code 83 of any of the modules. This can be used to change the build of a given 84 module depending on the application that needs it, instead of modifying 85 the Android.mk file itself. 86 87 IMPORTANT WARNING: +++++++++++++++++++++++++++++++++++++++++++++++++++ 88 + 89 + All paths in these flags should be relative to the top-level NDK 90 + directory. For example, if you have the following setup: 91 + 92 + sources/foo/Android.mk 93 + sources/bar/Android.mk 94 + 95 + To specify in foo/Android.mk that you want to add the path to the 96 + 'bar' sources during compilation, you should use: 97 + 98 + APP_CFLAGS += -Isources/bar 99 + 100 + Or alternatively: 101 + 102 + APP_CFLAGS += -I$(LOCAL_PATH)/../bar 103 + 104 + Using '-I../bar' will *NOT* work since it will be equivalent to 105 + '-I$NDK_ROOT/../bar' instead. 106 + 107 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 108 109 NOTE: In android-ndk-1.5_r1, this only applied to C sources, not C++ ones. 110 This has been corrected to match the full Android build system. 111 112 APP_CXXFLAGS 113 An alias for APP_CPPFLAGS, to be considered obsolete as it may disappear 114 in a future release of the NDK. 115 116 APP_CPPFLAGS 117 A set of C++ compiler flags passed when building C++ sources *only*. 118 119 NOTE: In android-ndk-1.5_r1, this applied to both C and C++ sources. 120 This has been corrected to match the full Android build system. 121 You can now use APP_CFLAGS for flags that shall apply to C and 122 C++ sources. 123 124 APP_BUILD_SCRIPT 125 By default, the NDK build system will look for a file named Android.mk 126 under $(APP_PROJECT_PATH)/jni, i.e. for the file: 127 128 $(APP_PROJECT_PATH)/jni/Android.mk 129 130 If you want to override this behaviour, you can define APP_BUILD_SCRIPT 131 to point to an alternate build script. A non-absolute path will always 132 be interpreted as relative to the NDK's top-level directory. 133 134 APP_ABI 135 By default, the NDK build system will generate machine code for the 136 'armeabi' ABI. This corresponds to an ARMv5TE based CPU with software 137 floating point operations. You can use APP_ABI to select a different 138 ABI. 139 140 For example, to support hardware FPU instructions on ARMv7 based devices, 141 use: 142 143 APP_ABI := armeabi-v7a 144 145 Or to support the IA-32 instruction set, use: 146 147 APP_ABI := x86 148 149 Or to support the MIPS instruction set, use: 150 151 APP_ABI := mips 152 153 Or to support all at the same time, use: 154 155 APP_ABI := armeabi armeabi-v7a x86 mips 156 157 Or even better, since NDK r7, you can also use the special value 158 'all' which means "all ABIs supported by this NDK release": 159 160 APP_ABI := all 161 162 For the list of all supported ABIs and details about their usage and 163 limitations, please read docs/CPU-ARCH-ABIS.html 164 165 APP_STL 166 By default, the NDK build system provides C++ headers for the minimal 167 C++ runtime library (/system/lib/libstdc++.so) provided by the Android 168 system. 169 170 However, the NDK comes with alternative C++ implementations that you can 171 use or link to in your own applications. Define APP_STL to select one of 172 them. Examples are: 173 174 APP_STL := stlport_static --> static STLport library 175 APP_STL := stlport_shared --> shared STLport library 176 APP_STL := system --> default C++ runtime library 177 178 For more information on the subject, please read docs/CPLUSPLUS-SUPPORT.html 179 180 APP_GNUSTL_FORCE_CPP_FEATURES 181 In prior NDK versions, the simple fact of using the GNU libstdc++ 182 runtime (i.e. by setting APP_STL to either 'gnustl_static' or 183 'gnustl_shared') enforced the support for exceptions and RTTI in all 184 generated machine code. This could be problematic in specific, but rare, 185 cases, and also generated un-necessarily bigger code for projects that 186 don't require these features. 187 188 This bug was fixed in NDK r7b, but this means that if your code requires 189 exceptions or RTTI, it should now explicitely say so, either in your 190 APP_CPPFLAGS, or your LOCAL_CPPFLAGS / LOCAL_CPP_FEATURES definitions. 191 192 To make it easier to port projects to NDK r7b and later, one can 193 optionally defined APP_GNUSTL_CPP_FEATURES to contain one or more of the 194 following values: 195 196 exceptions -> to enforce exceptions support for all modules. 197 rtti -> to enforce rtti support for all modules. 198 199 For example, to get the exact same behaviour than NDK r7: 200 201 APP_GNUSTL_FORCE_CPP_FEATURES := exceptions rtti 202 203 IMPORTANT: This variable is provided here as a convenience to make it 204 easier to transition to a newer version of the NDK. It will 205 be removed in a future revision. We thus encourage all 206 developers to modify the module definitions properly instead 207 of relying on it here. 208 209 APP_SHORT_COMMANDS 210 The equivalent of LOCAL_SHORT_COMMANDS for your whole project. See the 211 documentation for this variable in docs/ANDROID-MK.html. 212 213 A trivial Application.mk file would be: 214 215 -------------- cut here ------------------------- 216 APP_PROJECT_PATH := <path to project> 217 -------------- cut here ------------------------- 218 </pre></body></html> 219
