questions about "how to find_package"

[lizhiwei0304]

-- The C compiler identification is GNU 5.4.0
-- The CXX compiler identification is GNU 5.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done

********Find package in Module Mode!
CMAKE_MODULE_PATH =
CMAKE_LIBRARY_ARCHITECTURE = x86_64-linux-gnu

********Find package in Config Mode!
-- Found PkgConfig: /usr/bin/pkg-config (found version "0.29.1")

Found result using pkg-config:
PKG_TINYSPlINE_PATH = /opt/ros/kinetic/lib/pkgconfig:/opt/ros/kinetic/lib/x86_64-linux-gnu/pkgconfig
_FOUND =
_PREFIX =
_LIBRARIES =
_INCLUDE_DIRS =
_VERSION =
-- Could NOT find TINYSPlINE (missing: TINYSPlINE_INCLUDE_DIR TINYSPlINE_LIBRARY_DIR)
CMake Error at cmake/Findtinyspline.cmake:48 (message):
Could not find tinyspline
Call Stack (most recent call first):
CMakeLists.txt:17 (find_package)

tinyspline config file path:

1. cmake cache var 'CMAKE_PREFIX_PATH' =
2. env var 'CMAKE_PREFIX_PATH' = /opt/ros/kinetic
3. env var 'PATH' = /opt/ros/kinetic/bin:/home/lizhiwei/bin:/home/lizhiwei/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
4. cache var 'CMAKE_SYSTEM_PREFIX_PATH' = /usr/local;/usr;/;/usr;/usr/local
   CMake Error: The following variables are used in this project, but they are set to NOTFOUND.
   Please set them or make sure they are set and tested correctly in the CMake files:
   TINYSPlINE_INCLUDE_DIR (ADVANCED)
   used as include directory in directory /home/lizhiwei/Documents/cmake_tutorial/find_package_demo
   used as include directory in directory /home/lizhiwei/Documents/cmake_tutorial/find_package_demo
   used as include directory in directory /home/lizhiwei/Documents/cmake_tutorial/find_package_demo

-- Configuring incomplete, errors occurred!
See also "/home/lizhiwei/Documents/cmake_tutorial/find_package_demo/build/CMakeFiles/CMakeOutput.log".

how to solve this issue.

[ytiang]

I'm not very clear what is your issue? It seems that you want to use Module Mode to accomplish exercise. You can not find the install_demo_package by using Module Mode, because I don't provide related .pc file. Please read the find_package tutorial more carefully and try to use Config Mode to accomplish our exercise.
By the way, you should describe you issue more detailed. Such as your purpose, your exact operations causing the problem, the complete outputs... You can use this issue template to describe your problem.