Merge pull request #3 from daixtrose/add-toplevel-cmake

Add toplevel CMake file

.gitignore

@@ -32,4 +32,5 @@
 *.app
 
 build_*/*
-.vscode/*
+.vscode/*
+build/*

CMakeLists.txt

@@ -0,0 +1,13 @@
+cmake_minimum_required(VERSION 3.29)
+
+project(cplusplus-primer)
+
+include(ExternalProject)
+
+foreach(subproject example_1 example_2 example_3 example_4 library_1)
+    ExternalProject_Add(${subproject}
+        SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/${subproject}
+        STEP_TARGETS build
+        INSTALL_COMMAND ""
+    )
+endforeach()

README.md

@@ -14,6 +14,7 @@ A short introduction to C++. The examples build on top of each other. A special
   - Use for testing small C++ code snippets
 - [Craig Scott: "Professional CMake"](https://crascit.com/professional-cmake/)    
   - The one and only book you need about build systems 
+- [HSF - More Modern CMake](https://hsf-training.github.io/hsf-training-cmake-webpage/index.html)
 
 ## List of Subprojects
 

example_2/CMakeLists.txt

@@ -11,7 +11,7 @@ add_executable(example_2
 # add_subdirectory(../library_1 ../build_library_1)
 # but be aware of parallel builds!
 # In general, keep builds separate. KISS principle!
-add_subdirectory(../library_1 build_library_1)
+add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/../library_1 build_library_1)
 
 target_link_libraries(
     ${PROJECT_NAME}

example_3/CMakeLists.txt

@@ -18,7 +18,12 @@ include(FetchContent)
 # since the code for every dependency is stored on disk exactly once.
 FetchContent_Declare(
     library_1
-    SOURCE_DIR ../library_1
+
+    # Quote from Craig Scott, "Professional CMake":
+    # CMAKE_CURRENT_SOURCE_DIR is the directory of the CMakeLists.txt file currently being
+    # processed by CMake. It is updated each time a new file is processed as a result of an
+    # add_subdirectory() call and is restored back again when processing of that directory is complete.
+    SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../library_1
 )
 
 FetchContent_MakeAvailable(library_1)

example_4/CMakeLists.txt

@@ -18,7 +18,7 @@ include(FetchContent)
 # since the code for every dependency is stored on disk exactly once.
 FetchContent_Declare(
     library_1
-    SOURCE_DIR ../library_1
+    SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../library_1
 )
 
 FetchContent_MakeAvailable(library_1)

example_4/README.md

@@ -123,7 +123,7 @@ Here we illustrate recommended ways to use `cmake` in a **portable way**. See [t
 Create a subdirectory `build_example_4` and prepare the build system for the source in `example_4` in this subdirectory:
 
 ```bash
-cmake -D CMAKE_BUILD_TYPE=Release -B build_example_4 -S example_4
+cmake -D CMAKE_BUILD_TYPE=Release -B build_example_4 -S example_4 --fresh
 # for debug builds use   
 # cmake -D CMAKE_BUILD_TYPE=Debug -B build_example_4 -S example_4
 ```
@@ -133,7 +133,7 @@ cmake -D CMAKE_BUILD_TYPE=Release -B build_example_4 -S example_4
 Call `cmake` from the top level like this:
 
 ```bash
-cmake --build build_example_4 --config Release --target example_4
+cmake --build build_example_4 --config Release --target example_4 --clean-first
 ```
 
 ### Creating release packages