![]() See the table in the Build numbers document to map Android code names and version numbers to API levels. The major/minor version number given to an Android OS has no meaning when it comes to determining its API level. Be sure your users understand the implications of doing so. This behavior can be altered by following the section about weak symbols. If it does load, it may not behave as expected. An NDK application running on a device with an API level lower than the target will often not load at all. By default, APIs that are not present in the targeted API level cannot be linked directly, but may be accessed via dlsym. The API level targeted by an NDK application determines which APIs will be exposed for use by the application. Any time this doc refers to an API level, OS version, or target version, it is referring to the application's minSdkVersion. See the uses-sdk documentation for more information.įor NDK code, the only relevant value is the minimum supported version. These are minSdkVersion, maxSdkVersion, and targetSdkVersion respectively. OS VersionsĪs users are distributed over a wide variety of Android OS versions (see the Distribution dashboard), applications have a minimum and maximum supported version, as well as a targeted version. Alternatively, use the Play Console to exclude CPUs without NEON to disallow your app from being installed on those devices. To support non-NEON devices, pass -mfpu=vfpv3-d16 when compiling. NEON can significantly improve application performance.Ĭlang automatically enables NEON for all API levels. The Android CDD has required NEON support since that version, but it is possible that extant devices that were upgraded to Marshmallow do not include NEON support. This is supported by all 64-bit ARM devices and nearly all 32-bit ARM devices running at least Android Marshmallow (API 23). Android no longer supports ARMv5, but if your build system mistakenly targets ARMv5 the less efficient Thumb-1 will be used. By default, Clang will generate ARM code as opposed to Thumb for the armv7a-linux-androideabi target. The ARM or Thumb instruction sets are selected by passing -marm or -mthumb to Clang respectively. ndk-build and the NDK’s CMake toolchain file generate Thumb code by default. However, smaller code makes more effective use of a processor‘s instruction cache, so benchmarking is necessary to determine which is more effective for a given application. Thumb code is smaller but may perform worse than ARM. ![]() Thumbģ2-bit ARM can be built using either the Thumb or ARM instruction sets. To programatically determine the list of supported ABIs, their bitness, as well as their deprecation status and whether or not it is recommended to build them by default, use /meta/abis.json. Both NEON and non-NEON ARMv7 code uses the ARMv7 system and toolchains. Note: Strictly speaking ARMv7 with NEON is a different ABI from ARMv7 without NEON, but it is not a system ABI. The values of these variables for each architecture are as follows except where otherwise noted: Name This document will make use of, , and in describing paths and arguments. ![]() While in general this means that an app with only 32-bit libraries can run on 64-bit capable devices, the 64-bit ABI will have improved performance. 64-bit devices usually also support the 32-bit variant of their architecture, but this may not always be the case. NDK applications must build libraries for every architecture they support. For Android, each architecture supports only one ABI.Īndroid supports multiple architectures: ARM32, ARM64, x86, and x86_64. An ABI (application binary interface) is different from an architecture in that it also specifies a calling convention, size and alignment of types, and other implementation details. Note: In general an architecture may have multiple ABIs. Historically Binutils was used and remains available during the transition but is deprecated and will soon be removed from the NDK. These include Clang for compilation, LLD for linking, and other LLVM tools for other tasks. ![]() The NDK uses the LLVM family of tools for building C/C++ code. ![]()
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