02_shared_libraries

How to build (and link against to) a shared library

Let us create two shared libraries libmathematics.so and libphysics.so and link our main.cc against them

CMake

• Create a file CMakeLists.txt (case sensitive) with proper commands
• Create a build directory and cd in it (e.g. mkdir build_cmake && cd build_cmake)
• Run cmake /path/to/CMakeLists.txt (e.g. cmake ..)
• Compile with make

CMake useful commands

add_library(name_of_the_lib SHARED src_1.cc src_2.cc)

target_link_libraries(exe name_of_the_lib)

In add_library omit the prefix lib in the name of the library. To define a library named libmathematics.so I can write

add_libary(mathematics SHARED ...)

The call to target_link_libraries must be in the same CMakeLists.txt where exe has been defined.

Meson

• Create a file meson.build with proper commands

• Populate the build directory and go there

  • you can ask to meson to create it

    meson build_meson && cd build_meson

  • or you create it and call meson from there mkdir build_meson && cd build_meson

    mkdir build_meson && cd build_meson && meson ..

• Compile with ninja

Meson useful commands

a_lib = library('name_of_the_lib', ['src_1.cc', 'src_2.cc'],
                include_directories : inc_dirs)

executable('exe_name', 
           ['source/file1.cc', 'other/suource/file.cc'], 
           include_directories: inc,
           link_with: [a_lib])

inc_dirs and inc are object returned by the function include_directories()