2025-06-16 (3 VO): CMake, And A Little Git#

CMake #

Dependencies #

Node/Target Definitions, Basic Visualization #

run-door (through add_executable)

add_executable(run-door run-door.cpp)
target_link_libraries(run-door door)

door (through add_library)

src/door/CMakeLists.txt#

add_library(
  door

  door.h
  door.cpp

  ...
)

Visualizing

$ cd ~/My-Builds/FH-STECE2023-x86_64
$ cmake --graphviz dependencies.dot ~/My-Projects/FH-STECE2023
$ dot -Tpng dependencies.dot > dependencies.png
$ loupe dependencies.png

Install `libgpiod`, And Visualize Again #

Optional Dependencies

src/door/CMakeLists.txt#

if (LIBGPIOD_FOUND)                                    # <-- set toplevel by find_package(LIBGPIOD)
  target_link_libraries(door LIBGPIOD::LIBGPIOD)
else()
  message(WARNING "door will not use libgpiod (which has not been found). note that this might lead to errors in the build process")
endif()

Install libgpiod, and try again

# dnf install libgpiod-devel

$ pwd
/home/jfasch/My-Builds/FH-STECE2023-x86_64
$ rm -rf *                                        # <-- LIBGPIOD_FOUND is cached
$ cmake --graphviz dependencies.dot ~/My-Projects/FH-STECE2023
$ dot -Tpng dependencies.dot > dependencies.png
$ loupe dependencies.png

⟶ more dependencies

Include Paths #

Build information like include paths are propagated along reverse edges

src/door/CMakeLists.txt#

# build information (include path) for our users
target_include_directories(
  door

  PUBLIC

  ${CMAKE_CURRENT_SOURCE_DIR}/..                       # <-- users have to e.g. say #include <door/motor.h>
)

Git: Merge, Rebase #

Merge #

Create branch merge-demo
- Modify bin/run-demo.cpp
- Commit
Checkout main
- Modify bin/run-demo.cpp
- Commit
Show: gitk --all
Merge: on main, git merge merge-demo
Show: gitk --all

Rebase #

Create branch rebase-demo
- Modify bin/run-demo.cpp
- Commit
Checkout main
- Modify bin/run-demo.cpp
- Commit
Show: gitk --all
Checkout rebase-demo
Transplant onto main: git rebase main
Show: gitk --all

What Is An OS Image? How Do I Write It Onto SD-Card?#

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