CMake allows us to create libraries used by the OpenCV build system. Factorizing shared code among multiple applications is a common and useful practice in software development. In big applications, or common code shared in multiple applications, this practice is very useful. In this case, we do not create a binary executable, but instead we create a compiled file that includes all the functions, classes, and so on. We can then share this library file with other applications without sharing our source code.
CMake includes the add_library function to this end:
# Create our hello library
add_library(Hello hello.cpp hello.h)
# Create our application that uses our new library
add_executable(executable main.cpp)
# Link our executable with the new library
target_link_libraries(executable Hello)
The lines starting with # add comments and are ignored...