From f2b0515fdd1cb84bebe24cac59498b682b49de80 Mon Sep 17 00:00:00 2001
From: Johannes Stoelp <johannes.stoelp@gmail.com>
Date: Sat, 4 Nov 2023 21:34:00 +0100
Subject: cmake: add note about PRIVATE/PUBLIC/INTERFACE

---
 src/development/README.md |  1 +
 src/development/cmake.md  | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)
 create mode 100644 src/development/cmake.md

(limited to 'src/development')

diff --git a/src/development/README.md b/src/development/README.md
index 117ef17..af18a02 100644
--- a/src/development/README.md
+++ b/src/development/README.md
@@ -4,6 +4,7 @@
 - [c++](./c++.md)
 - [glibc](./glibc.md)
 - [gcc](./gcc.md)
+- [cmake](./cmake.md)
 - [make](./make.md)
 - [ld.so](./ld.so.md)
 - [symbol versioning](./symbolver.md)
diff --git a/src/development/cmake.md b/src/development/cmake.md
new file mode 100644
index 0000000..d0bbeea
--- /dev/null
+++ b/src/development/cmake.md
@@ -0,0 +1,39 @@
+# cmake(1)
+
+## `PRIVATE` / `PUBLIC` / `INTERFACE`
+
+These modifier control where properties for a given target are visible.
+
+- `PRIVATE`: Only for the target itself.
+- `PUBLIC`: For the target itself and anyone linking against it.
+- `INTERFACE`: Only for anyone linking against the target.
+
+The following gives an example for preprocessor definitions specified on a
+library target. This behaves in the same way for other properties like for
+example include directories.
+```cmake
+# CMakeLists.txt
+
+cmake_minimum_required(VERSION 3.14)
+project(moose)
+
+# -- LIBRARY
+add_library(liba STATIC liba.cc)
+target_compile_definitions(liba PUBLIC DEF_PUBLIC)
+target_compile_definitions(liba PRIVATE DEF_PRIVATE)
+target_compile_definitions(liba INTERFACE DEF_INTERFACE)
+
+# -- APPLICATION
+add_executable(main main.cc)
+target_link_libraries(main liba)
+```
+
+```sh
+> touch liba.cc; echo "int main() {}" > main.cc
+> cmake -B build -S . -G Ninja
+> ninja -C build -j1 --verbose
+[1/4] /usr/bin/c++ -DDEF_PRIVATE -DDEF_PUBLIC  [..] .../liba.cc
+[2/4] [..]
+[3/4] /usr/bin/c++ -DDEF_INTERFACE -DDEF_PUBLIC [..] .../main.cc
+[4/4] [..]
+```
-- 
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