The ability to do so can be useful for specifying additional macro definitions or compile options. The build system can handle this setting automatically for you, using the relevant information in the Application. Doing it this way allows the build system to generate useful data files used during debugging.
If the current module is a shared library or an executable, this variable will force these libraries to be linked into the resulting binary. If the current module is a static library, this variable simply indicates that other modules depending on the current one will also depend on the listed libraries.
This variable is the list of shared libraries modules on which this module depends at runtime. This information is necessary at link time, and to embed the corresponding information in the generated file. For more information on whole archives, see the GNU ld documentation for the --whole-archive flag. This variable is useful when there are circular dependencies among several static libraries.
When you use this variable to build a shared library, it will force the build system to add all object files from your static libraries to the final binary. The same is not true, however, when generating executables. This variable contains the list of additional linker flags for use in building your shared library or executable. It enables you to use the -l prefix to pass the name of specific system libraries. The list of other linker flags for the build system to use when building your shared library or executable.
For example, to use the ld. By default, when the build system encounters an undefined reference encountered while trying to build a shared, it will throw an undefined symbol error. This error can help you catch bugs in your source code. To disable this check, set this variable to true.
Note that this setting may cause the shared library to load at runtime. Defining this variable as arm forces the build system to generate the module's object files in bit arm mode. The following example shows how to do this:. You can also instruct the build system to only build specific sources in arm mode by appending. For example, the following example tells the build system to always compile bar. This variable only matters when you are targeting the armeabi-v7a ABI. For this reason, you must perform runtime detection to be able to safely use this code at runtime.
For more information, see Neon support and CPU features. Alternatively, you can use the. In the following example, the build system compiles foo. If you use both suffixes,. By default, the build system compiles code with format string protection.
Doing so forces a compiler error if a non-constant format string is used in a printf -style function. This protection is on by default, but you can disable it by setting the value of this variable to true. We do not recommend doing so without a compelling reason. For example, consider the following pair of modules: foo and bar , which depends on foo :. In addition, the relationship among modules is transitive: If zoo depends on bar , which in turn depends on foo , then zoo also inherits all flags exported from foo.
Finally, the build system does not use exported flags when building locally i. It is useful in cases where, for example, bar. Prepend -l to the name of each library you specify. It does this due to the way Unix linkers work. This variable is typically useful when module foo is a static library and has code that depends on a system library.
In this example, the build system puts -llog at the end of the linker command when it builds libbar. Doing so tells the linker that, because libbar. Doing so forces the build system to use syntax for archives containing intermediate object files or linking libraries. This feature can be useful on Windows, where the command line accepts a maximum of only of characters, which can be too small for complex projects.
It also impacts the compilation of individual source files, placing nearly all compiler flags inside list files, too. Note that any value other than true will revert to the default behaviour. Set this variable to true when building static libraries. Doing so will generate a thin archive , a library file that does not contain object files, but instead just file paths to the actual objects that it would normally contain.
This is useful to reduce the size of your build output. The drawback is that such libraries cannot be moved to a different location all paths inside them are relative. Valid values are true , false or empty. A default value can be set in your Application. Defining this variable causes the following things to occur:. The filter must be a standalone shell command that takes the name of the input file as its first argument, and the name of the output file as the second one.
This macro returns the path of the last included makefile, which typically is the current Android. Due to the way GNU Make works, what this macro really returns is the path of the last makefile that the build system included when parsing the build scripts. For this reason, you should not call my-dir after including another file. You can avoid this problem by putting additional includes after everything else in the Android.
If it is not feasible to structure the file in this way, save the value of the first my-dir call into another variable. Returns the list of Android. You can use this function to provide deep-nested source directory hierarchies to the build system. By default, the NDK only looks for files in the directory containing the Android.
Returns the path of the parent makefile in the inclusion tree the path of the makefile that included the current one. Returns the path of the grandparent makefile in the inclusion tree the path of the makefile that included the current one. A function that allows you to find and include a module's Android.
A typical example is as follows:. Content and code samples on this page are subject to the licenses described in the Content License. Home Guides Reference Samples Downloads. Build your project. Architectures and CPUs. Debug and profile. High-performance audio. OpenSL ES. Machine learning. Android Developers. Overview The Android. Basics Before exploring the syntax in detail, it is useful to start by understanding the basics of what a Android.
Variables and macros The build system provides many possible variables for use in the Android. The build system uses these internally. Lower-case names, such as my-dir. The build system uses these internally, as well. The NDK build system will. This also means that, when updating to newer releases of the NDK,.
Before describing the syntax in details, let's consider the simple. This source file implements a simple shared library that. Its content is:. Now, let's explain these lines:. It is used to locate source files in the development tree. In this example,. This is needed because all build. Note that the build system will automatically add proper. In other words,. If you name your module 'libfoo', the build system will not. This is to support Android.
Android platform sources, would you need to use these. Note that you should. It is. Don't forget the initial dot i. There are more complex examples in the samples directories, with commented. This is the list of variables you should either rely on or define in. You can define other variables for your own usage, but. If you need to define your own convenience variables in an Android. These GNU Make variables are defined by the build system before.
Note that under certain circumstances. You must include. Points to a build script that collects all the information about the. Note that you. Example usage:. Static libraries are not copied into your. Points to a build script used to specify a prebuilt shared library. You can reference the prebuilt library in another module using.
Name of the target CPU architecture as it is specified by the. This is 'arm' for any ARM-compatible. Name of the target Android platform when this Android. For example, 'android-3' correspond to Android 1. Two values are supported at the moment:. However, the value has been redefined to better. For more details about architecture ABIs and corresponding.
The concatenation of target platform and abi, it really is defined. By default, this will be 'androidarmeabi'. Up to Android NDK 1. NDK-provided function macros:. The following are GNU Make 'function' macros, and must be evaluated. They return textual information. Returns the path of the last included Makefile, which typically is. This is useful to define. Do not call my-dir after including another file. For example, consider the following example:.
The problem here is that the second call to 'my-dir' will define. For this reason, it's better to put additional includes after. If this is not convenient, save the value of the first my-dir call. Returns a list of Android. For example, consider the following. This function can be used to provide deep-nested source directory. Note that by default, the NDK. Returns the path of the current Makefile i. Returns the path of the parent Makefile in the inclusion tree,. A function that allows you to find and include the Android.
A typical example is:. Module-description variables:. The following variables are used to describe your module to the build. This variable is used to give the path of the current file. This is the name of your module. It must be unique among all.
This is basic program for NDK beginners, OpenCV library can be imported here and you can do image processing applications also. Download android-ndk PDF android-ndk Getting started with android-ndk. Example Using Android Studio 2. Next, to integrate NDK with Android Studio, after creating a new android project, In gradle — local properties add location of sdk path like sdk. Here I am for simple example just adding two numbers and returning value to android java.
Then, in main activity pass the input and get output for native class file. And obtained output is displayed in screen by passing to TextView. Then now run the application, you will get output for this example as Skip to content. Branches Tags. Could not load branches. Could not load tags. Go back. Launching Xcode If nothing happens, download Xcode and try again. Launching Visual Studio Code Your codespace will open once ready.
Latest commit. Retire jcenter in samples Git stats 1, commits. Failed to load latest commit information. Update to AGP Android gradle plugin 4. May 5, Switching to github Action for CI Feb 2, Jun 29, Dec 19, Nov 17,