Structure - Subdirectories, Dependencies, and Include Paths

Source

08-structure/
├── CMakeLists.txt
├── bin
│   ├── CMakeLists.txt
│   ├── hello-first.c
│   └── hello-second.c
└── libhello
    ├── CMakeLists.txt
    ├── hello.c
    ├── hello.h
    ├── hello-name.c
    └── hello-name.h

• 08-structure/CMakeLists.txt

• 08-structure/bin/CMakeLists.txt

• 08-structure/bin/hello-first.c

• 08-structure/bin/hello-second.c

• 08-structure/libhello/CMakeLists.txt

• 08-structure/libhello/hello.h

• 08-structure/libhello/hello.c

• 08-structure/libhello/hello-name.c

• 08-structure/libhello/hello-name.h

Reorganization

Documentation

• add_subdirectory()

• Descend into libhello/ and bin/

  • Move files around

  • Move CMake code around

  • Miss to care about include paths

  Toplevel CMakeLists.txt

  add_subdirectory(libhello)
  add_subdirectory(bin)
  

$ make
[ 14%] Building C object libhello/CMakeFiles/hello.dir/hello.c.o
[ 28%] Building C object libhello/CMakeFiles/hello.dir/hello-name.c.o
[ 42%] Linking C shared library libhello.so
[ 42%] Built target hello
[ 57%] Building C object bin/CMakeFiles/hello-first.dir/hello-first.c.o
/home/jfasch/work/jfasch-home/trainings/material/soup/cmake/code/bin/hello-first.c:1:10: fatal error: hello.h: No such file or directory
    1 | #include "hello.h"
      |          ^~~~~~~~~
compilation terminated.
make[2]: *** [bin/CMakeFiles/hello-first.dir/build.make:76: bin/CMakeFiles/hello-first.dir/hello-first.c.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:144: bin/CMakeFiles/hello-first.dir/all] Error 2
make: *** [Makefile:136: all] Error 2

Dependencies, And Target Properties

Documentation

• target_include_directories()

• Dependencies are in place

  

• Only code has been moved around

• ⟶ hello header files are now too far away from bin/ targets

• Let hello carry that information

  target_include_directories(hello PUBLIC .)
  

• ⟶ propagated to dependers

• PUBLIC vs. PRIVATE

  • PUBLIC propagated to dependers (see/show .dependers dot file) so they can find the headers of targets they depend on

  • PRIVATE does not propagate. Purpose: e.g., one might structure (internally only) a target’s source code into src/ and inc/ for example.