1 2 NOTES FOR ANDROID PLATFORMS 3 =========================== 4 5 Requirement details 6 ------------------- 7 8 Beside basic tools like perl and make you'll need to download the Android 9 NDK. It's available for Linux, macOS and Windows, but only Linux 10 version was actually tested. There is no reason to believe that macOS 11 wouldn't work. And as for Windows, it's unclear which "shell" would be 12 suitable, MSYS2 might have best chances. NDK version should play lesser 13 role, the goal is to support a range of most recent versions. 14 15 Configuration 16 ------------- 17 18 Android is a naturally cross-compiled target and you can't use ./config. 19 You have to use ./Configure and name your target explicitly; there are 20 android-arm, android-arm64, android-mips, android-mip64, android-x86 21 and android-x86_64 (*MIPS targets are no longer supported with NDK R20+). 22 Do not pass --cross-compile-prefix (as you might be tempted), as it will 23 be "calculated" automatically based on chosen platform. Though you still 24 need to know the prefix to extend your PATH, in order to invoke 25 $(CROSS_COMPILE)clang [*gcc on NDK 19 and lower] and company. (Configure 26 will fail and give you a hint if you get it wrong.) Apart from PATH 27 adjustment you need to set ANDROID_NDK_HOME environment to point at the 28 NDK directory. If you're using a side-by-side NDK the path will look 29 something like /some/where/android-sdk/ndk/<ver>, and for a standalone 30 NDK the path will be something like /some/where/android-ndk-<ver>. 31 Both variables are significant at both configuration and compilation times. 32 The NDK customarily supports multiple Android API levels, e.g. android-14, 33 android-21, etc. By default latest API level is chosen. If you need to 34 target an older platform pass the argument -D__ANDROID_API__=N to Configure, 35 with N being the numerical value of the target platform version. For example, 36 to compile for Android 10 arm64 with a side-by-side NDK r20.0.5594570 37 38 export ANDROID_NDK_HOME=/home/whoever/Android/android-sdk/ndk/20.0.5594570 39 PATH=$ANDROID_NDK_HOME/toolchains/llvm/prebuilt/linux-x86_64/bin:$ANDROID_NDK_HOME/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin:$PATH 40 ./Configure android-arm64 -D__ANDROID_API__=29 41 make 42 43 Older versions of the NDK have GCC under their common prebuilt tools directory, so the bin path 44 will be slightly different. EG: to compile for ICS on ARM with NDK 10d: 45 46 export ANDROID_NDK_HOME=/some/where/android-ndk-10d 47 PATH=$ANDROID_NDK_HOME/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86_64/bin:$PATH 48 ./Configure android-arm -D__ANDROID_API__=14 49 make 50 51 Caveat lector! Earlier OpenSSL versions relied on additional CROSS_SYSROOT 52 variable set to $ANDROID_NDK_HOME/platforms/android-<api>/arch-<arch> to 53 appoint headers-n-libraries' location. It's still recognized in order 54 to facilitate migration from older projects. However, since API level 55 appears in CROSS_SYSROOT value, passing -D__ANDROID_API__=N can be in 56 conflict, and mixing the two is therefore not supported. Migration to 57 CROSS_SYSROOT-less setup is recommended. 58 59 One can engage clang by adjusting PATH to cover same NDK's clang. Just 60 keep in mind that if you miss it, Configure will try to use gcc... 61 Also, PATH would need even further adjustment to cover unprefixed, yet 62 target-specific, ar and ranlib. It's possible that you don't need to 63 bother, if binutils-multiarch is installed on your Linux system. 64 65 Another option is to create so called "standalone toolchain" tailored 66 for single specific platform including Android API level, and assign its 67 location to ANDROID_NDK_HOME. In such case you have to pass matching 68 target name to Configure and shouldn't use -D__ANDROID_API__=N. PATH 69 adjustment becomes simpler, $ANDROID_NDK_HOME/bin:$PATH suffices. 70 71 Running tests (on Linux) 72 ------------------------ 73 74 This is not actually supported. Notes are meant rather as inspiration. 75 76 Even though build output targets alien system, it's possible to execute 77 test suite on Linux system by employing qemu-user. The trick is static 78 linking. Pass -static to Configure, then edit generated Makefile and 79 remove occurrences of -ldl and -pie flags. You would also need to pick 80 API version that comes with usable static libraries, 42/2=21 used to 81 work. Once built, you should be able to 82 83 env EXE_SHELL=qemu-<arch> make test 84 85 If you need to pass additional flag to qemu, quotes are your friend, e.g. 86 87 env EXE_SHELL="qemu-mips64el -cpu MIPS64R6-generic" make test 88
Indexes created Sun Mar 01 05:31:48 UTC 2026