add shared_recording cpp example

examples/cpp/CMakeLists.txt

@@ -1,12 +1,15 @@
 add_subdirectory(clock)
+add_subdirectory(custom_collection_adapter)
 add_subdirectory(dna)
+add_subdirectory(shared_recording)
 add_subdirectory(minimal)
 add_subdirectory(spawn_viewer)
-add_subdirectory(custom_collection_adapter)
 
 add_custom_target(examples)
+
 add_dependencies(examples example_clock)
+add_dependencies(examples example_custom_collection_adapter)
 add_dependencies(examples example_dna)
+add_dependencies(examples example_shared_recording)
 add_dependencies(examples example_minimal)
 add_dependencies(examples example_spawn_viewer)
-add_dependencies(examples example_custom_collection_adapter)

examples/cpp/shared_recording/CMakeLists.txt

@@ -0,0 +1,32 @@
+cmake_minimum_required(VERSION 3.16...3.27)
+
+# If you use the example outside of the Rerun SDK you need to specify
+# where the rerun_c build is to be found by setting the `RERUN_CPP_URL` variable.
+# This can be done by passing `-DRERUN_CPP_URL=<path to rerun_sdk_cpp zip>` to cmake.
+if(DEFINED RERUN_REPOSITORY)
+    add_executable(example_shared_recording main.cpp)
+    rerun_strict_warning_settings(example_shared_recording)
+else()
+    project(example_shared_recording LANGUAGES CXX)
+
+    add_executable(example_shared_recording main.cpp)
+
+    # Set the path to the rerun_c build.
+    set(RERUN_CPP_URL "https://github.com/rerun-io/rerun/releases/latest/download/rerun_cpp_sdk.zip" CACHE STRING "URL to the rerun_cpp zip.")
+    option(RERUN_FIND_PACKAGE "Whether to use find_package to find a preinstalled rerun package (instead of using FetchContent)." OFF)
+
+    if(RERUN_FIND_PACKAGE)
+        find_package(rerun_sdk REQUIRED)
+    else()
+        # Download the rerun_sdk
+        include(FetchContent)
+        FetchContent_Declare(rerun_sdk URL ${RERUN_CPP_URL})
+        FetchContent_MakeAvailable(rerun_sdk)
+    endif()
+
+    # Rerun requires at least C++17, but it should be compatible with newer versions.
+    set_property(TARGET example_shared_recording PROPERTY CXX_STANDARD 17)
+endif()
+
+# Link against rerun_sdk.
+target_link_libraries(example_shared_recording PRIVATE rerun_sdk)

examples/cpp/shared_recording/README.md

@@ -0,0 +1,26 @@
+---
+title: Shared Recording
+rust: https://github.com/rerun-io/rerun/tree/latest/examples/rust/shared_recording/src/main.rs?speculative-link
+cpp: https://github.com/rerun-io/rerun/tree/latest/examples/cpp/shared_recording/main.cpp?speculative-link
+---
+
+<picture>
+  <img src="https://static.rerun.io/shared_recording/c3da85f1d4c158b8c7afb6bd3278db000b58049d/full.png" alt="">
+  <source media="(max-width: 480px)" srcset="https://static.rerun.io/shared_recording/c3da85f1d4c158b8c7afb6bd3278db000b58049d/480w.png">
+  <source media="(max-width: 768px)" srcset="https://static.rerun.io/shared_recording/c3da85f1d4c158b8c7afb6bd3278db000b58049d/768w.png">
+  <source media="(max-width: 1024px)" srcset="https://static.rerun.io/shared_recording/c3da85f1d4c158b8c7afb6bd3278db000b58049d/1024w.png">
+  <source media="(max-width: 1200px)" srcset="https://static.rerun.io/shared_recording/c3da85f1d4c158b8c7afb6bd3278db000b58049d/1200w.png">
+</picture>
+
+This example demonstrates how to use `RecordingId`s to create a single shared recording across multiple processes.
+
+To build it from a checkout of the repository (requires a Rust toolchain):
+```bash
+cmake .
+cmake --build . --target example_shared_recording
+```
+
+Run the following multiple times, and you'll see that each invocation adds data to the existing recording rather than creating a new one:
+```bash
+./examples/cpp/shared_recording/example_shared_recording
+```

examples/cpp/shared_recording/main.cpp

@@ -0,0 +1,22 @@
+#include <unistd.h>
+#include <iostream>
+#include <sstream>
+
+#include <rerun.hpp>
+#include <rerun/demo_utils.hpp>
+
+using rerun::demo::grid3d;
+
+int main() {
+    const auto rec =
+        rerun::RecordingStream("rerun_example_shared_recording", "my_shared_recording");
+    rec.spawn().exit_on_failure();
+
+    int pid = getpid();
+    std::ostringstream oss;
+    oss << "Hello from " << pid;
+
+    rec.log("updates", rerun::TextLog(oss.str()));
+
+    std::cout << "Run me again to append more data to the recording!" << std::endl;
+}