CODEWITHSUNDEEP
c++cmake
reid-sutherland
reid-sutherland

Reputation: 43

CMake linker cannot find library that does not begin with "lib"

I am using CMake to compile an application which uses the HSImage library on github. After installing with pip, the HSI library generates a shared library file, in my case it is created at /usr/src/HSI/HSI.cpython-36m-aarch64-linux-gnu.so

I am trying to link this library to my application with CMake, but the CMake find_library method is having some trouble finding the library. Here is the relevant part of my CMakeLists.txt file:

CMakeLists.txt

set(HSI_DIR /usr/src/HSI)
find_library(HSI_LIB HSI.cpython-36m-aarch64-linux-gnu PATHS ${HSI_DIR})
message(STATUS "HSI:  ${HSI_LIB}")  # outputs /usr/src/HSI/HSI.cpython-36m-aarch64-linux-gnu.so

add_executable(${TARGET_NAME} <sources...>)
target_link_directories(${TARGET_NAME} PUBLIC ${HSI_DIR})
target_link_libraries(${TARGET_NAME}
        ${HSI_LIB}
        <other libs...>
        -Wl,--unresolved-symbols=ignore-in-shared-libs
    )

When building, this produces the following error message:

cd /home/nvidia/projects/HsiInference/build;/usr/local/bin/cmake --build "/home/nvidia/projects/HsiInference/build" --target hsi_inference_onnx  --  ;

Scanning dependencies of target hsi_inference_onnx
[ 14%] Building CXX object CMakeFiles/hsi_inference_onnx.dir/targets/HsiInferenceOnnx/main_onnx.cpp.o
[ 28%] Building CXX object CMakeFiles/hsi_inference_onnx.dir/targets/HsiInferenceOnnx/HsiInferenceOnnx.cpp.o
[ 42%] Building CXX object CMakeFiles/hsi_inference_onnx.dir/src/ftpnano.cpp.o
[ 57%] Building CXX object CMakeFiles/hsi_inference_onnx.dir/src/getOptions.cpp.o
[ 71%] Building CXX object CMakeFiles/hsi_inference_onnx.dir/src/logger.cpp.o
[ 85%] Building CXX object CMakeFiles/hsi_inference_onnx.dir/src/utils.cpp.o
[100%] Linking CXX executable hsi_inference_onnx_debug
CMakeFiles/hsi_inference_onnx.dir/build.make:245: recipe for target 'hsi_inference_onnx_debug' failed
CMakeFiles/Makefile2:123: recipe for target 'CMakeFiles/hsi_inference_onnx.dir/all' failed
**/usr/bin/ld: cannot find -lHSI.cpython-36m-aarch64-linux-gnu**
**collect2: error: ld returned 1 exit status**
make[3]: *** [hsi_inference_onnx_debug] Error 1
make[2]: *** [CMakeFiles/hsi_inference_onnx.dir/all] Error 2
CMakeFiles/Makefile2:130: recipe for target 'CMakeFiles/hsi_inference_onnx.dir/rule' failed
make[1]: *** [CMakeFiles/hsi_inference_onnx.dir/rule] Error 2
Makefile:196: recipe for target 'hsi_inference_onnx' failed
make: *** [hsi_inference_onnx] Error 2

Build failed.

The important part:

/usr/bin/ld: cannot find -lHSI.cpython-36m-aarch64-linux-gnu
collect2: error: ld returned 1 exit status

From what I have gathered, target_link_libraries simply adds -l<library_name> to the link command, and -l<library_name> assumes that there is a file called lib<library_name>.so to link, which is not the case here. How can I get CMake to link the library properly despite the weird filename?

NOTE: I am able to get the project to build by doing the following:

This changes the link command to -lhsi instead, which is able to find the renamed/soft-linked library file. HOWEVER, this is not ideal for me and the original question remains unanswered :)

Upvotes: 1

Views: 985

Answers (1)

yflelion
yflelion

Reputation: 1746

For libraries with weird filename you should add : before the filename. Be careful, like mentioned in https://linux.die.net/man/1/ld : If namespec is of the form :filename, ld will search the library path for a file called filename, otherwise it will search the library path for a file called libnamespec.a (namespec is what comes after -l).

For your example you should replace ${HSI_LIB} in target_link_libraries by :${HSI_LIB}.so.

Upvotes: 3

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