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I am using Android Studio 2.2.2 with cmake and Android NDK. I have a problem linking .a library (Static lib).

Here is my cmake:

# Sets the minimum version of CMake required to build the native # library. You should either keep the default value or only pass a # value of 3.4.0 or lower. cmake_minimum_required(VERSION 3.4.1) set(CMAKE_VERBOSE_MAKEFILE on) # Creates and names a library, sets it as either STATIC # or SHARED, and provides the relative paths to its source code. # You can define multiple libraries, and CMake builds it for you. # Gradle automatically packages shared libraries with your APK. add_library(lib_webp SHARED IMPORTED ) set_target_properties(lib_webp PROPERTIES IMPORTED_LOCATION src/main/jni/${ANDROID_ABI}/libwebp.so) add_library( # Sets the name of the library. game-lib # Sets the library as a shared library. SHARED # Provides a relative path to your source file(s). # Associated headers in the same location as their source # file are automatically included. src/main/cpp/main.cpp src/main/cpp/android_native_app_glue.c ) target_include_directories(game-lib PRIVATE ../../../../libs/headers/android ) include_directories($ENV{NDK_MODULE_PATH}/sources/android/native_app_glue/) # Specifies libraries CMake should link to your target library. You # can link multiple libraries, such as libraries you define in the # build script, prebuilt third-party libraries, or system libraries. target_link_libraries( # Specifies the target library. game-lib # Links the target library to the log library # included in the NDK. # ${log-lib} # Specifies the name of the NDK library that # you want CMake to locate. log android OpenSLES z GLESv2 EGL dl ) add_definitions(-g -DANDROID -Wno-write-strings -fsigned-char -Wno-conversion-null) TARGET_LINK_LIBRARIES(game-lib libtheoraplayer.a)

My linker reports an error

arm-linux-androideabi/bin\ld: error: cannot find -ltheoraplayer

error: undefined reference to 'TheoraVideoManager::TheoraVideoManager(int)'

which is a part of libtheoraplayer.a. Did anyone had similar problem? Any idea how to solve this?

I have the Static lib libtheoraplayer.a present at that location. I even have the Shared lib also, libtheoraplayer.so but I can`t link it either.

Any advice would be appreciated.

Cheers.

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  • I have the Static lib libtheoraplayer.a present at that location. - Where exactly do you have this library? I see no link_directories calls in you code, so why do you expect a linker to find the library? Commented Nov 1, 2016 at 10:58
  • I am new to cmake so please forgive me if I ask stupid questions. I used the old system with Android.mk for Android NDK. I am not aware that I need link_directories? The lib is the Theora Player already built (theora.org) and I need to import it to my project. link_directioris should point to the source file of Theora? Commented Nov 1, 2016 at 11:02
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    You need to point CMake where it should search library for link. There are several ways to do that: Using absolute path to the library file in target_link_libraries, or using IMPORTed library target with absolute path, or using 'link_directories' call with directory where to search the library. In all cases the library file is libtheoraplayer.a, which you mention in the question. Commented Nov 1, 2016 at 11:16
  • Well I have TARGET_LINK_LIBRARIES(game-lib libtheoraplayer.a) at the end of the file, please check the file I added in the question. I will try to move this to another location and give a relative path to it. Commented Nov 1, 2016 at 11:28
  • Again, you use non-absolute filename for library. CMake (linker) tries to find this library .. and fails. This is what the error message talks about. CMake doesn't automatically search libraries in current source/build directory, you need to specify this explicitely using one of the ways I describe above. Commented Nov 1, 2016 at 11:36

1 Answer 1

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To post the answer. As Tsyvarev said, the problem with non-absolute file name for library. When I used absoulte path it worked like a charm.

Thank you. Cheers.

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2 Comments

I managed to link .a libraries with relative path too. Here is an example: target_link_libraries(game ${CMAKE_CURRENT_SOURCE_DIR}/../../../libs/cricket/lib/libck.a)
You should put your comment in the answer because the comment is the answer. A bit frustrating having to edit this when upgrading Android studio. But it works.

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