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

Question

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:
Delete the project's build directory to clear CMake caches
Rename the file or create a symbolic link to libhsi.so
Change CMakeLists.txt to find_library(HSI_LIB hsi PATHS ${HSI_DIR})
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 :)

Answer 1

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.