Screenplay: Adding `SQLite3` External Dependency#

Add SQLite3 Capability To Datalogger #

Add to toolcase/data-logger …
- sink-sqlite3.h
- sink-sqlite3.cpp

Use in firmware/data-logger.cpp

if (argc != 2) {
    std::cerr << "Usage: " << argv[0] << " <SQLITE3-DB>" << std::endl;
    std::cerr << "  (Create: \"" << SinkSQLite3::create_table_statement << "\")" << std::endl;
    return 1;
}

...

auto sink = std::make_unique<SinkSQLite3>(argv[1]);

Build

In file included from .../toolcase/data-logger/src/sink-sqlite3.cpp:1:
.../toolcase/data-logger/./include/public/sink-sqlite3.h:5:10: fatal error: sqlite3.h: No such file or directory
    5 | #include <sqlite3.h>
      |          ^~~~~~~~~~~

`FIND_PACKAGE()`#

Pulling in parameters for SQLite3

Toplevel CMakeLists.txt#

find_package(SQLite3)      # <--- continues if not found

Not found unless sqlite3 is available

$ cmake ...
...
-- Could NOT find SQLite3 (missing: SQLite3_INCLUDE_DIR SQLite3_LIBRARY)
...

Not an error though
⟶ error remains: sqlite3.h: No such file or directory
Could continue if we could handle optional dependencies
⟶ Later (Screenplay: Making SQLite3 Optional (target_compile_definitions()), Screenplay: Making SQLite3 Optional (configure_file()))

`FIND_PACKAGE(... REQUIRED)`#

C code cannot handle SQLite3 non-availablility

⟶ better to fail early/clearly

find_package(SQLite3 REQUIRED)

$ cmake ...
CMake Error at /usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:230 (message):
  Could NOT find SQLite3 (missing: SQLite3_INCLUDE_DIR SQLite3_LIBRARY)
Call Stack (most recent call first):
  /usr/share/cmake/Modules/FindPackageHandleStandardArgs.cmake:600 (_FPHSA_FAILURE_MESSAGE)
  /usr/share/cmake/Modules/FindSQLite3.cmake:54 (find_package_handle_standard_args)
  CMakeLists.txt:9 (find_package)

Install SQLite3
```
$ sudo dnf install sqlite-devel
```

Try again

$ cmake ...
...
-- Found SQLite3: /usr/include (found version "3.42.0")
...

Bringing A New Node Into The Graph: Theory #

Find-modules (if successful) usually define a node in the dependency graph
Propagate properties across graphs’s edges
From FindSQLite3
- SQLite::SQLite3: imported target ⟶ most important
- SQLite3_INCLUDE_DIRS: include path (via
  target_include_directories())
- SQLite3_LIBRARIES: nodes to depend on (via
  target_link_libraries)
- SQLite3_VERSION: additional information
- SQLite3_FOUND: to check for availablity in CMake code

Temporarily add, to see that information

message("SQLite3_INCLUDE_DIRS ${SQLite3_INCLUDE_DIRS}")
message("SQLite3_LIBRARIES ${SQLite3_LIBRARIES}")
message("SQLite3_VERSION ${SQLite3_VERSION}")
message("SQLite3_FOUND ${SQLite3_FOUND}")

But that is mostly not relevant! (Read on)

Bringing A New Node Into The Graph: Practice #

toolcase/data-logger has
- sink-sqlite3.h
- sink-sqlite3.cpp
⟶ depends on node SQLite::SQLite3

Add dependency there …

target_link_libraries(data-logger SQLite::SQLite3)

And that’s all!

Screenplay: Adding SQLite3 External Dependency#

Add SQLite3 Capability To Datalogger#

FIND_PACKAGE()#

FIND_PACKAGE(... REQUIRED)#

Bringing A New Node Into The Graph: Theory#

Bringing A New Node Into The Graph: Practice#