In Android Studio, gradle creates directory .externalNativeBuild
under the module root, for each module that has NDK integration, via CMake or ndk-build.android
For CMake, the gradle plugin is quite verbose. For each build variant it creates separate subdirectory, e.g. .externalNativeBuild/cmake/debug/x86
or .externalNativeBuild/cmake/release/armeabi-v7a
, etc.c++
Each directory contains some useful files: cmake_build_command.txt describes the actual parameters passed to CMake; android_gradle_build.json shows what parameters the gradle plugin derived for your binaries; from build.ninja you can deduce the how these parameters were applied for each compilation or linkage step.json
For ndk-build
, the android_gradle_build.json
file is also quite useful. ndkBuild_build_command.txt
lists all parameters passed to ndk-build command, and ndkBuild_build_output.txt
is the unabridged output of that command. You can easily add V=1
to the arguments, e.g.app
externalNativeBuild { ndkBuild { cppFlags "-std=c++11" arguments "APP_STL=c++_static", "APP_OPTIM=release", "NDK_DEBUG=0", "V=1" abiFilters "armeabi-v7a" } }
For CMake
, the relevant argument is "-DCMAKE_VERBOSE_MAKEFILE:BOOL=ON"
(see explanation and alternatives):less
externalNativeBuild { cmake { cppFlags "-std=c++11" arguments "-DCMAKE_VERBOSE_MAKEFILE:BOOL=ON" abiFilters "armeabi-v7a" } }
Without CMAKE_VERBOSE_MAKEFILE
, the Gradle Console displays:ide
:app:externalNativeBuildDebug Build native-lib armeabi-v7a [1/2] Building CXX object CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.o [2/2] Linking CXX shared library ../../../../build/intermediates/cmake/debug/obj/armeabi-v7a/libnative-lib.so
With "-DCMAKE_VERBOSE_MAKEFILE:BOOL=ON"
, I get tons of output:post
:app:externalNativeBuildDebug Build native-lib armeabi-v7a [1/2] /Users/alex/Library/Android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++ --target=armv5te-none-linux-androideabi --gcc-toolchain=/Users/alex/Library/Android/sdk/ndk-bundle/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64 --sysroot=/Users/alex/Library/Android/sdk/ndk-bundle/platforms/android-14/arch-arm -Dnative_lib_EXPORTS -isystem /Users/alex/Library/Android/sdk/ndk-bundle/sources/cxx-stl/gnu-libstdc++/4.9/include -isystem /Users/alex/Library/Android/sdk/ndk-bundle/sources/cxx-stl/gnu-libstdc++/4.9/libs/armeabi-v7a/include -isystem /Users/alex/Library/Android/sdk/ndk-bundle/sources/cxx-stl/gnu-libstdc++/4.9/include/backward -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -march=armv5te -mtune=xscale -msoft-float -fno-integrated-as -mthumb -Wa,--noexecstack -Wformat -Werror=format-security -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -march=armv5te -mtune=xscale -msoft-float -fno-integrated-as -mthumb -Wa,--noexecstack -Wformat -Werror=format-security -O0 -fno-limit-debug-info -O0 -fno-limit-debug-info -fPIC -MD -MT CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.o -MF CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.o.d -o CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.o -c /Users/alex/test/egl/app/src/main/cpp/native-lib.cpp [2/2] : && /Users/alex/Library/Android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++ --target=armv5te-none-linux-androideabi --gcc-toolchain=/Users/alex/Library/Android/sdk/ndk-bundle/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64 --sysroot=/Users/alex/Library/Android/sdk/ndk-bundle/platforms/android-14/arch-arm -fPIC -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -march=armv5te -mtune=xscale -msoft-float -fno-integrated-as -mthumb -Wa,--noexecstack -Wformat -Werror=format-security -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -march=armv5te -mtune=xscale -msoft-float -fno-integrated-as -mthumb -Wa,--noexecstack -Wformat -Werror=format-security -O0 -fno-limit-debug-info -O0 -fno-limit-debug-info -Wl,--build-id -Wl,--warn-shared-textrel -Wl,--fatal-warnings -Wl,--no-undefined -Wl,-z,noexecstack -Qunused-arguments -Wl,-z,relro -Wl,-z,now -Wl,--build-id -Wl,--warn-shared-textrel -Wl,--fatal-warnings -Wl,--no-undefined -Wl,-z,noexecstack -Qunused-arguments -Wl,-z,relro -Wl,-z,now -shared -Wl,-soname,libnative-lib.so -o ../../../../build/intermediates/cmake/debug/obj/armeabi-v7a/libnative-lib.so CMakeFiles/native-lib.dir/src/main/cpp/native-lib.cpp.o -llog -lEGL -lGLESv2 -lm "/Users/alex/Library/Android/sdk/ndk-bundle/sources/cxx-stl/llvm-libc++/libs/armeabi-v7a/libc++_static.a" "-latomic" && :
The obvious file .externalNativeBuild/cmake/debug/armeabi-v7a/cmake_build_output.txt
does not contain interesting information (unless you have problems with CMake configuration per se). Gradle does not write this output to file, but you can use command line redirection, see Where are Gradle logs?.gradle
Note: "-DCMAKE_VERBOSE_MAKEFILE:BOOL=ON"
does not seem to work anymore. "-DCMAKE_VERBOSE_MAKEFILE=ON"
worked for me. Not sure what has changed, I just installed android studio.ui