Libraries, And Dependencies#

Libraries And Executables#

  • Raw toolchain building a library: Object Code Archives/Static Libraries

  • Nothing is free: build instructions become more complex

  • Executable do not stand alone anymore

  • ⟶ depend on a library

  • ⟶ Dependency graph (directed and acyclic, ideally)

  • CMake terminology: graph nodes are called “targets” (inherited from make terminology)

05-static-libraries/CMakeLists.txt#
cmake_minimum_required(VERSION 3.16)
project(Demo)

add_library(hello                             # <-- target "hello"
  hello.h hello.c 
  hello-name.h hello-name.c)

add_executable(hello-first hello-first.c)     # <-- target "hello-first"
target_link_libraries(hello-first hello)      # <-- "hello-first" depends on "hello"

add_executable(hello-second hello-second.c)   # <-- target "hello-second"
target_link_libraries(hello-second hello)     # <-- "hello-second" depends on "hello"

Note

Header files are not compiled, but adding them is convenient for IDE usage.

Targets And Dependencies#

  • Executables depend on libraries

  • ⟶ dependencies

  • hello-first depends on hello

  • hello-second depends on hello

05-static-libraries/CMakeLists.txt#
target_link_libraries(hello-first hello)      # <--- "hello-first" depends on "hello"
target_link_libraries(hello-second hello)     # <--- "hello-second" depends on "hello"

  • Executables may depend on libraries

  • Libraries may depend on libraries

  • (Nothing ever depends on an executable)

  • ⟶ Directed Acyclic Graph (DAG)

Visualizing Dependencies#

  • Project sanity: knowing your dependencies

  • ⟶ Graphviz package

Generating dot files#
$ pwd
/path/to/build/directory
$ cmake --graphviz=Demo.dot ~/work/jfasch-home/trainings/material/soup/cmake/05-static-libraries/
$ ls -l *.dot*
-rw-r--r--. 1 jfasch jfasch 1260 Jul 13 19:31 Demo.dot
-rw-r--r--. 1 jfasch jfasch  336 Jul 13 19:31 Demo.dot.hello.dependers
-rw-r--r--. 1 jfasch jfasch  222 Jul 13 19:31 Demo.dot.hello-first
-rw-r--r--. 1 jfasch jfasch  225 Jul 13 19:31 Demo.dot.hello-second
Convert into viewable image#
$ dot -Tpng Demo.dot > Demo.png
../../../../../../_images/Demo.png