How to fix “ld: symbol(s) not found for architecture x86_64” using C++, CMake and Tensorflow?

Question

I created a test project in C ++ using TensorFlow with CMake. But I have an error:

ld: symbol(s) not found for architecture x86_64

I think, I have an error in my CMake files. When I try compile via the terminal with gcc tensortest.cpp -ltensorflow -o tf , everything works fine.

I have two CMake files.

FindTensorFlow.cmake:

# Locates the tensorFlow library and include directories.
include(FindPackageHandleStandardArgs)
unset(TENSORFLOW_FOUND)

find_path(TensorFlow_INCLUDE_DIR
        NAMES
        tensorflow
        HINTS

        /usr/local/include/tensorflow)

find_library(TensorFlow_LIBRARY
        NAMES
        libtensorflow_framework.1.14.0.dylib
        libtensorflow_framework.1.dylib
        libtensorflow_framework.dylib
        libtensorflow.1.14.0.dylib
        libtensorflow.1.dylib
        libtensorflow.dylib
        HINTS
        /usr/local/lib)

# set TensorFlow_FOUND
find_package_handle_standard_args(TensorFlow DEFAULT_MSG TensorFlow_INCLUDE_DIR TensorFlow_LIBRARY)

# set external variables for usage in CMakeLists.txt
if(TENSORFLOW_FOUND)
  set(TensorFlow_LIBRARIES ${TensorFlow_LIBRARY})
  set(TensorFlow_INCLUDE_DIRS ${TensorFlow_INCLUDE_DIR})
endif()

# hide locals from GUI
mark_as_advanced(TensorFlow_INCLUDE_DIR TensorFlow_LIBRARY)

CMakeLists.txt

cmake_minimum_required(VERSION 3.15)
project(TensorFlowTest)

set(CMAKE_CXX_STANDARD 14)
list(APPEND CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake/")

find_package(TensorFlow REQUIRED)
include_directories(${TensorFlow_INCLUDE_DIRS} ${TensorFlow_LIBRARIES})

add_executable(TensorFlowTest main.cpp)
target_link_libraries(TensorFlowTest ${TensorFlow_INCLUDE_DIRS} ${TensorFlow_LIBRARIES})

And one main.cpp

#include <stdio.h>
#include <tensorflow/c/c_api.h>

int main() {
    printf("Hello from TensorFlow C library version %s\n", TF_Version());
    return 0;
}

When reload project, I have a CMake message:

-- Found TensorFlow: /usr/local/include  
-- Configuring done
WARNING: Target "TensorFlowTest" requests linking to directory "/usr/local/include".  Targets may link only to libraries.  CMake is dropping the item.
-- Generating done
-- Build files have been written to: /Users/neikr/CLionProjects/TensorFlowTest/cmake-build-debug

And when compiling:

Scanning dependencies of target TensorFlowTest
[ 50%] Building CXX object CMakeFiles/TensorFlowTest.dir/main.cpp.o
[100%] Linking CXX executable TensorFlowTest
Undefined symbols for architecture x86_64:
  "_TF_Version", referenced from:
      _main in main.cpp.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[3]: *** [TensorFlowTest] Error 1
make[2]: *** [CMakeFiles/TensorFlowTest.dir/all] Error 2
make[1]: *** [CMakeFiles/TensorFlowTest.dir/rule] Error 2
make: *** [TensorFlowTest] Error 2

Update

I tried make with VERBOSE=1 and I get this output:

/Applications/CLion.app/Contents/bin/cmake/mac/bin/cmake -S/Users/neikr/CLionProjects/TensorFlowTest -B/Users/neikr/CLionProjects/TensorFlowTest --check-build-system CMakeFiles/Makefile.cmake 0
/Applications/CLion.app/Contents/bin/cmake/mac/bin/cmake -E cmake_progress_start /Users/neikr/CLionProjects/TensorFlowTest/CMakeFiles /Users/neikr/CLionProjects/TensorFlowTest/CMakeFiles/progress.marks
/Applications/Xcode.app/Contents/Developer/usr/bin/make -f CMakeFiles/Makefile2 all
/Applications/Xcode.app/Contents/Developer/usr/bin/make -f CMakeFiles/TensorFlowTest.dir/build.make CMakeFiles/TensorFlowTest.dir/depend
cd /Users/neikr/CLionProjects/TensorFlowTest && /Applications/CLion.app/Contents/bin/cmake/mac/bin/cmake -E cmake_depends "Unix Makefiles" /Users/neikr/CLionProjects/TensorFlowTest /Users/neikr/CLionProjects/TensorFlowTest /Users/neikr/CLionProjects/TensorFlowTest /Users/neikr/CLionProjects/TensorFlowTest /Users/neikr/CLionProjects/TensorFlowTest/CMakeFiles/TensorFlowTest.dir/DependInfo.cmake --color=
/Applications/Xcode.app/Contents/Developer/usr/bin/make -f CMakeFiles/TensorFlowTest.dir/build.make CMakeFiles/TensorFlowTest.dir/build
[ 50%] Linking CXX executable TensorFlowTest
/Applications/CLion.app/Contents/bin/cmake/mac/bin/cmake -E cmake_link_script CMakeFiles/TensorFlowTest.dir/link.txt --verbose=1
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++  -g -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk -Wl,-search_paths_first -Wl,-headerpad_max_install_names  CMakeFiles/TensorFlowTest.dir/main.cpp.o  -o TensorFlowTest -Wl,-rpath,/usr/local/lib /usr/local/lib/libtensorflow_framework.1.14.0.dylib 
Undefined symbols for architecture x86_64:
  "_TF_Version", referenced from:
      _main in main.cpp.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [TensorFlowTest] Error 1
make[1]: *** [CMakeFiles/TensorFlowTest.dir/all] Error 2
make: *** [all] Error 2

Also, I tried adding message("TensorFlow_LIBRARIES: ${TensorFlow_LIBRARIES}") to the end of my CMake and I get this message:

TensorFlow_LIBRARIES: /usr/local/lib/libtensorflow_framework.1.14.0.dylib

Answer 1

Based on your print-out from the message() command, it is more clear what is going on. In your FindTensorFlow.cmake file, the find_library() call only finds one library ( libtensorflow_framework.1.14.0.dylib ), which is expected behavior:

Once one of the calls succeeds the result variable will be set and stored in the cache so that no call will search again.

When more than one value is given to the NAMES option this command by default will consider one name at a time and search every directory for it.

Thus, once find_library() finds the libtensorflow_framework library, the search stops . If you want to also find libtensorflow.dylib , which may help with your link error, you have to specify another find_library() call, using a different TensorFlow_ variable. So changing that section of your FindTensorFlow.cmake to something like this should help:

find_library(TensorFlow_LIBRARY
        NAMES
        libtensorflow.1.14.0.dylib
        libtensorflow.1.dylib
        libtensorflow.dylib
        HINTS
        /usr/local/lib)

find_library(TensorFlow_FRAMEWORK_LIBRARY
        NAMES
        libtensorflow_framework.1.14.0.dylib
        libtensorflow_framework.1.dylib
        libtensorflow_framework.dylib
        HINTS
        /usr/local/lib)

# set TensorFlow_FOUND
find_package_handle_standard_args(TensorFlow DEFAULT_MSG 
    TensorFlow_INCLUDE_DIR 
    TensorFlow_LIBRARY 
    TensorFlow_FRAMEWORK_LIBRARY
)