1 'ndk-build' Overview 2 === 3 4 I. Usage: 5 --------- 6 7 The Android NDK r4 introduced a new tiny shell script, named 'ndk-build', 8 to simplify building machine code. 9 10 The script is located at the top-level directory of the NDK, and shall 11 be invoked from the command-line when in your application project 12 directory, or any of its sub-directories. For example: 13 14 cd $PROJECT 15 $NDK/ndk-build 16 17 Where $NDK points to your NDK installation path. You can also create an 18 alias or add $NDK to your PATH to avoid typing it every time. 19 20 21 II. Options: 22 ------------ 23 24 All parameters to 'ndk-build' are passed directly to the underlying GNU Make 25 command that runs the NDK build scripts. Notable uses include: 26 27 ndk-build --> rebuild required machine code. 28 ndk-build clean --> clean all generated binaries. 29 30 ndk-build NDK_DEBUG=1 --> generate debuggable native code. 31 32 ndk-build V=1 --> launch build, displaying build commands. 33 34 ndk-build -B --> force a complete rebuild. 35 36 ndk-build -B V=1 --> force a complete rebuild and display build 37 commands. 38 39 ndk-build NDK_LOG=1 --> display internal NDK log messages 40 (used for debugging the NDK itself). 41 42 ndk-build NDK_DEBUG=1 --> force a debuggable build (see below) 43 ndk-build NDK_DEBUG=0 --> force a release build (see below) 44 45 ndk-build NDK_HOST_32BIT=1 --> Always use toolchain in 32-bit (see below) 46 47 ndk-build NDK_APPLICATION_MK=<file> 48 --> rebuild, using a specific Application.mk pointed to by 49 the NDK_APPLICATION_MK command-line variable. 50 51 ndk-build -C <project> --> build the native code for the project 52 path located at <project>. Useful if you 53 don't want to 'cd' to it in your terminal. 54 55 56 III. Debuggable versus Release builds: 57 -------------------------------------- 58 59 In NDK r5, ndk-build has been modified to make it easier to switch between 60 release and debug builds. This is done by using the NDK_DEBUG variable. 61 For example: 62 63 $NDK/ndk-build NDK_DEBUG=1 => forces the generation of debug binaries 64 $NDK/ndk-build NDK_DEBUG=0 => forces the generation of release binaries 65 66 If you don't specify NDK_DEBUG, ndk-build will keep its default behaviour, 67 which is to inspect the AndroidManifest.xml, if any, and see if its 68 <application> element has android:debuggable="true". 69 70 > IMPORTANT: 71 If you use the build tools of SDK r8 (or higher), you 72 won't need to touch your AndroidManifest.xml file at all! 73 74 > That's because if you build a debug package (e.g. with 75 "ant debug" or the corresponding option of the ADT plugin), 76 the tool will automatically pick the native debug files 77 generated with NDK_DEBUG=1. 78 79 Also, as a convenience, the release and debug object files generated by the 80 NDK are now stored in different directories (e.g. obj/local/<abi>/objs and 81 obj/local/<abi>/objs-debug). This avoids having to recompile all your sources 82 when you switch between these two modes (even when you only modified one or 83 two source files). 84 85 86 IV. 64-bit and 32-bit toolchains: 87 --------------------------------- 88 89 Some toolchains come with both 64-bit and 32-bit versions. For example, 90 directories `$NDK/toolchain/<name>/prebuilt` and `$NDK/prebuilt` may contains both 91 "`linux-x86`" and "`linux-x86_64`" folders for Linux tools in 32-bit and 64-bit modes, 92 respectively. The ndk-build script automatically chooses a 64-bit version of the 93 toolchain if the host OS supports it. You can force the use of a 32-bit toolchain by 94 using NDK_HOST_32BIT=1 either in your envorinment or on the ndk-build command-line. 95 96 Note that 64-bit tools utilize host resources better (faster, handle larger 97 programs, etc) and they should function identically to their 32-bit counterparts. 98 Ie. 64-bit toolchains still generate 32-bit binaries for Android. 99 100 101 V. Requirements: 102 ---------------- 103 104 You need GNU Make 3.81 or later to use 'ndk-build' or the NDK in general. 105 The build scripts will detect that you're using a non-compliant Make tool 106 and will complain with an error message. 107 108 If you have GNU Make 3.81 installed, but that it is not launched by the 109 default 'make' command, define GNUMAKE in your environment to point to it 110 before launching 'ndk-build'. For example: 111 112 GNUMAKE=/usr/local/bin/gmake ndk-build 113 114 Or to make the change more permanent: 115 116 export GNUMAKE=/usr/local/bin/gmake 117 ndk-build 118 119 Adapt to your shell and GNU Make 3.81 installation location. 120 121 You may override other host prebuilt tools in $NDK/prebuilt/<OS>/bin 122 with the following environment variables 123 124 NDK_HOST_AWK=<path-to-awk> 125 126 NDK_HOST_ECHO=<path-to-echo> 127 128 NDK_HOST_CMP=<path-to-cmp> 129 130 131 VI. Internals: 132 -------------- 133 134 'ndk-build' itself is a tiny wrapper around GNU Make, its purpose is simply 135 to invoke the right NDK build script, it is equivalent to; 136 137 $GNUMAKE -f $NDK/build/core/build-local.mk [parameters] 138 139 Where '$GNUMAKE' points to GNU Make 3.81 or later, and $NDK points to your 140 NDK installation directory. 141 142 Use this knowledge if you want to invoke the NDK build script from other 143 shell scripts (or even your own Makefiles). 144
