Using FluidSynth on Android crashes at runtime

[selimbousbih]

I'm trying to build an android app using FluidSynth, I managed to compile the project but when loading the native library, the app crashes with the following error: java.lang.UnsatisfiedLinkError: dlopen failed: library "libomp.so" not found

This is my CMakeLists configuration

# Sets the minimum version of CMake required to build the native library.
cmake_minimum_required(VERSION 3.4.0)

# Create a variable fluidsynth_DIR to specify where the fluidsynth library is located.
set(fluidsynth_DIR ${CMAKE_CURRENT_SOURCE_DIR}/fluidsynth)

add_compile_options(-std=c++17 -fopenmp -lgomp)

# Our code (native-lib.cpp) will be calling fluidsynth functions, so we add the fluidsynth binaries as dependencies of our code.

add_library(libFLAC SHARED IMPORTED)

set_target_properties(libFLAC PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libFLAC.so)

add_library(libfluidsynth SHARED IMPORTED)
set_target_properties(libfluidsynth PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libfluidsynth.so)

add_library(libfluidsynth-assetloader SHARED IMPORTED)
set_target_properties(libfluidsynth-assetloader PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libfluidsynth-assetloader.so)

add_library(libgio-2.0 SHARED IMPORTED)
set_target_properties(libgio-2.0 PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libgio-2.0.so)

add_library(libglib-2.0 SHARED IMPORTED)
set_target_properties(libglib-2.0 PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libglib-2.0.so)

add_library(libgmodule-2.0 SHARED IMPORTED)
set_target_properties(libgmodule-2.0 PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libgmodule-2.0.so)

add_library(libgobject-2.0 SHARED IMPORTED)
set_target_properties(libgobject-2.0 PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libgobject-2.0.so)

add_library(libgthread-2.0 SHARED IMPORTED)
set_target_properties(libgthread-2.0 PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libgthread-2.0.so)

add_library(libinstpatch-1.0 SHARED IMPORTED)
set_target_properties(libinstpatch-1.0 PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libinstpatch-1.0.so)

add_library(liboboe SHARED IMPORTED)
set_target_properties(liboboe PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/liboboe.so)

add_library(libogg SHARED IMPORTED)
set_target_properties(libogg PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libogg.so)

add_library(libopus SHARED IMPORTED)
set_target_properties(libopus PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libopus.so)

add_library(libpcre SHARED IMPORTED)
set_target_properties(libpcre PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libpcre.so)

add_library(libpcreposix SHARED IMPORTED)
set_target_properties(libpcreposix PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libpcreposix.so)

add_library(libsndfile SHARED IMPORTED)
set_target_properties(libsndfile PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libsndfile.so)

add_library(libvorbis SHARED IMPORTED)
set_target_properties(libvorbis PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libvorbis.so)

add_library(libvorbisenc SHARED IMPORTED)
set_target_properties(libvorbisenc PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libvorbisenc.so)

add_library(libvorbisfile SHARED IMPORTED)
set_target_properties(libvorbisfile PROPERTIES IMPORTED_LOCATION ${fluidsynth_DIR}/lib/${ANDROID_ABI}/libvorbisfile.so)

# Library that will be called directly from JAVA
add_library(native-lib SHARED native-lib.cpp)

# Specifies the directory where the C or C++ source coude will look the #include <yourlibrary.h> header files
target_include_directories(native-lib PRIVATE ${fluidsynth_DIR}/include)

# Link everything alltogether. Notice that native-lib should be the first element in the list.

target_link_libraries(
        native-lib
        libFLAC
        libfluidsynth
        libfluidsynth-assetloader
        libgio-2.0
        libglib-2.0
        libgmodule-2.0
        libgobject-2.0
        libgthread-2.0
        libinstpatch-1.0
        liboboe
        libogg
        libopus
        libpcre
        libpcreposix
        libsndfile
        libvorbis
        libvorbisenc
        libvorbisfile
)

[derselbst]

First of all, this is not a crash. It's a runtime error that results in an exception. Exceptions can be handled gracefully.

Yes, fluidsynth has been compiled against openMP. This is correctly noted in the cmake\fluidsynth\FluidSynthConfig.cmake. You are not using this file. You are also not using the included pkg-config file. Instead, you have decided to import all of fluidsynth's dependencies manually. I would call this approach questionable.

The error you see is caused by the runtime linker failing to discover the libomp.so file included in the Android NDK. Try setting LD_LIBRARY_PATH accordingly or copy over the libs from the NDK into your runtime directory.

[selimbousbih]

Thanks for your answer, my approach was indeed incorrect. It's working now using a more recent version of the library with an approriate cmake version