cmake: freq vars + module example

9 files changed, 88 insertions, 0 deletions

diff --git a/src/development/cmake.md b/src/development/cmake.md
index acf2d6b..e8f9430 100644
--- a/src/development/cmake.md
+++ b/src/development/cmake.md
@@ -1,5 +1,20 @@
 # cmake(1)
 
+## Frequently used variables
+```
+# Install location.
+CMAKE_INSTALL_PREFIX=<path>
+
+# Generate compile_commands.json?
+CMAKE_EXPORT_COMPILE_COMMANDS={0,1}
+
+# Project build type.
+CMAKE_BUILD_TYPE={Debug, Release, RelWithDebInfo, MinSizeRel}
+
+# C++ standard.
+CMAKE_CXX_STANDARD={14,17,..}
+```
+
 ## `PRIVATE` / `PUBLIC` / `INTERFACE`
 
 These modifier control where properties for a given target are visible.
@@ -38,3 +53,21 @@ target_link_libraries(main liba)
 [3/4] /usr/bin/c++ -DDEF_INTERFACE -DDEF_PUBLIC [..] .../main.cc
 [4/4] [..]
 ```
+
+## `find_package` [[ref][cmake-find_package]]
+A small example to play with can be found in [cmake/module][src-module].
+
+```cmake
+find_package(Name MODULE)
+```
+Looks for `FindName.cmake` in paths given by `CMAKE_MODULE_PATH` and then builtin paths.
+
+```cmake
+find_package(Name CONFIG)
+```
+Looks for `name-config.cmake` or `NameConfig.cmake` in paths given by
+`CMAKE_PREFIX_PATH`, or path given by `Name_DIR` and then builtin paths.
+
+[cmake-include]: https://cmake.org/cmake/help/latest/command/include.html
+[cmake-find_package]: https://cmake.org/cmake/help/latest/command/find_package.html
+[src-module]: https://github.com/johannst/notes/tree/master/src/development/cmake/module
diff --git a/src/development/cmake/module/.gitignore b/src/development/cmake/module/.gitignore
new file mode 100644
index 0000000..378eac2
--- /dev/null
+++ b/src/development/cmake/module/.gitignore
@@ -0,0 +1 @@
+build
diff --git a/src/development/cmake/module/CMakeLists.txt b/src/development/cmake/module/CMakeLists.txt
new file mode 100644
index 0000000..f52d282
--- /dev/null
+++ b/src/development/cmake/module/CMakeLists.txt
@@ -0,0 +1,27 @@
+cmake_minimum_required(VERSION 3.10)
+project(hello-pkg)
+
+# Include as file.
+include(cmake/moose.cmake)
+# Include as module (search CMAKE_MODULE_PATH, then builtin paths).
+include(moose)
+
+# -- Foo package ---------------------------------------------------------------
+
+# Find module (uses CMAKE_MODULE_PATH, Foo_DIR, builtin paths).
+message("==> find_package(Foo MODULE)")
+find_package(Foo MODULE)
+
+# Find config (uses CMAKE_PREFIX_PATH, Foo_DIR, builtin paths).
+message("==> find_package(Foo CONFIG)")
+find_package(Foo CONFIG REQUIRED)
+
+# -- Bar package ---------------------------------------------------------------
+
+# Find module (uses CMAKE_MODULE_PATH, Bar_DIR, builtin paths).
+message("==> find_package(Bar MODULE)")
+find_package(Bar MODULE)
+
+# Find config (uses CMAKE_PREFIX_PATH, Bar_DIR, builtin paths).
+message("==> find_package(Bar CONFIG)")
+find_package(Bar CONFIG REQUIRED)
diff --git a/src/development/cmake/module/Makefile b/src/development/cmake/module/Makefile
new file mode 100644
index 0000000..39f0389
--- /dev/null
+++ b/src/development/cmake/module/Makefile
@@ -0,0 +1,14 @@
+DBG ?= n
+CMAKE_DBG-y = -DCMAKE_FIND_DEBUG_MODE=1
+
+all:
+	@# CMAKE_MODULE_PATH for include() and find_package module flows.
+	@# CMAKE_PREFIX_PATH for find_package config flow.
+	@# Bar_DIR package specific for find_package config flow.
+	cmake . -B build -DCMAKE_MODULE_PATH="cmake;foo;bar" -DCMAKE_PREFIX_PATH="foo" -DBar_DIR=bar $(CMAKE_DBG-$(DBG))
+
+debug:
+	$(MAKE) all DBG=y
+
+clean:
+	$(RM) -r build
diff --git a/src/development/cmake/module/bar/BarConfig.cmake b/src/development/cmake/module/bar/BarConfig.cmake
new file mode 100644
index 0000000..d5164cf
--- /dev/null
+++ b/src/development/cmake/module/bar/BarConfig.cmake
@@ -0,0 +1 @@
+message("BarConfig invoked")
diff --git a/src/development/cmake/module/bar/FindBar.cmake b/src/development/cmake/module/bar/FindBar.cmake
new file mode 100644
index 0000000..f2047ea
--- /dev/null
+++ b/src/development/cmake/module/bar/FindBar.cmake
@@ -0,0 +1,2 @@
+message("FindBar invoked")
+set(Bar_FOUND 1)
diff --git a/src/development/cmake/module/cmake/moose.cmake b/src/development/cmake/module/cmake/moose.cmake
new file mode 100644
index 0000000..3052671
--- /dev/null
+++ b/src/development/cmake/module/cmake/moose.cmake
@@ -0,0 +1,7 @@
+# Add include guard with the scope of the includers directory downwards.
+#include_guard(DIRECTORY)
+
+# Add global include guard (whole build).
+#include_guard(GLOBAL)
+
+message("moose invoked")
diff --git a/src/development/cmake/module/foo/FindFoo.cmake b/src/development/cmake/module/foo/FindFoo.cmake
new file mode 100644
index 0000000..0653bb8
--- /dev/null
+++ b/src/development/cmake/module/foo/FindFoo.cmake
@@ -0,0 +1,2 @@
+message("FindFoo invoked")
+set(Foo_FOUND 1)
diff --git a/src/development/cmake/module/foo/FooConfig.cmake b/src/development/cmake/module/foo/FooConfig.cmake
new file mode 100644
index 0000000..a575ef2
--- /dev/null
+++ b/src/development/cmake/module/foo/FooConfig.cmake
@@ -0,0 +1 @@
+message("FooConfig invoked")