From 3ec595ed49ff60f3ab75aada97873a583c1bd62a Mon Sep 17 00:00:00 2001
From: yadunund <yadunund@openrobotics.org>
Date: Fri, 3 Oct 2025 00:47:05 -0700
Subject: [PATCH] Log message for linktime composition on Windows (#640)

Signed-off-by: Yadunund <yadunund@openrobotics.org>
Co-authored-by: Alejandro Hernandez Cordero <ahcorde@gmail.com>
(cherry picked from commit 8c49a99ccbc130ddc82d726ce038943b78038f75)
---
 composition/README.md                    | 25 +-----------------------
 composition/src/linktime_composition.cpp |  7 +++++++
 2 files changed, 8 insertions(+), 24 deletions(-)

diff --git a/composition/README.md b/composition/README.md
index 94abf150b..21e5b27d0 100644
--- a/composition/README.md
+++ b/composition/README.md
@@ -59,30 +59,7 @@ Run the following command to load the libraries.
 ros2 run composition dlopen_composition `ros2 pkg prefix composition`/lib/libtalker_component.so `ros2 pkg prefix composition`/lib/liblistener_component.so
 ```
 
-#### Windows
-
-On Windows, we will need the `*.dll` files.
-Since command substitution will not work on Windows, you have to give the absolute path of the libraries.
-
-The libraries will be in `<path_to_your_ros2_installation>\bin\`, so we have to run.
-
-```bash
-ros2 run composition dlopen_composition <prefix_path>\bin\talker_component.dll <prefix_path>\bin\listener_component.dll
-```
-
-To get the `prefix_path` run
-
-```bash
-ros2 pkg prefix composition
-```
-
-For example if our `prefix_path` comes out to be `C:\pixi_ws\ros2-windows\` we will run
-
-```bash
-ros2 run composition dlopen_composition C:\pixi_ws\ros2-windows\bin\talker_component.dll C:\pixi_ws\ros2-windows\bin\listener_component.dll
-```
-
-### Linktime Composition
+### Linktime Composition (not supported on Windows)
 
 Similar to previous, this runs `linktime_composition` which **links all classes from libraries** that are registered under the **library_path** with the **linker**.
 
diff --git a/composition/src/linktime_composition.cpp b/composition/src/linktime_composition.cpp
index 0ae19b277..e9c0d6218 100644
--- a/composition/src/linktime_composition.cpp
+++ b/composition/src/linktime_composition.cpp
@@ -36,6 +36,13 @@ int main(int argc, char * argv[])
   std::vector<std::unique_ptr<class_loader::ClassLoader>> loaders;
   std::vector<rclcpp_components::NodeInstanceWrapper> node_wrappers;
 
+  // Linktime composition is not supported on Windows.
+  #ifdef _WIN32
+  RCLCPP_ERROR(logger, "Linktime composition is not supported on Windows.");
+  rclcpp::shutdown();
+  return 0;
+  #endif   // _WIN32
+
   std::vector<std::string> libraries = {
     // all classes from libraries linked by the linker (rather than dlopen)
     // are registered under the library_path ""