Modules

WARNING

Experimental. The module's contents may change between releases. If something you need is missing or does not compile, please open an issue.

RTXUI can be used as a C++ module: import rtxui; instead of #include <rtxui/rtxui.hpp>.

Building the module

Turn on RTXUI_BUILD_MODULE. It needs CMake 3.28 or newer and the Ninja (or Visual Studio) generator: Makefile generators cannot build modules.

cmake -B build -G Ninja -DRTXUI_BUILD_MODULE=ON
cmake --build build

Link your target against rtxui::module:

cmake_minimum_required(VERSION 3.28)  # Scans your sources for `import`.
# ...
target_link_libraries(my_app PRIVATE rtxui::module)

If your project has to declare an older minimum version, CMake does not look for import in your sources. Turn it on for the target instead: set_target_properties(my_app PROPERTIES CXX_SCAN_FOR_MODULES ON).

Using it

Three things differ from including the headers:

1. Bind() comes from <rtxui/bind.hpp>. It is a macro, and a module cannot export macros.
2. Include the standard headers you use. <rtxui/rtxui.hpp> brings in <string>, <vector> and others, and code often counts on that without noticing. The module makes none of them visible.
3. Put every #include before import rtxui;. GCC requires a header to be included before importing a module that also includes it.

#include <string>
#include <string_view>
#include <rtxui/bind.hpp>
import rtxui;

using namespace rtxui;

class Counter : public Component<Counter> {
 public:
  int count = 0;
  void Increment() { count++; }

  Counter() {
    Bind(count);
    Bind(Increment);
  }

  std::string_view view = R"html(
    <button onclick="Increment">Clicked {count} times</button>
  )html";
};

int main() {
  auto app = Ref<Counter>::New();
  Screen screen(app);
  screen.Loop();
}

Every example in example/ is also built this way and checked against its snapshot: see cmake/modules.cmake.

What the module exports

Component, Ref, Screen, Event, FieldSink, PostTask, PostDelayedTask, Diagnostic and SetDiagnosticHandler. That is what the examples use, and engine internals stay out. HeadlessScreen and the other testing helpers are not exported yet: test with the headers for now.

Known issues

• GCC 15 crashes ("internal compiler error: in nonnull_arg_p") at -O2 and above on a file that imports rtxui but includes neither <string> nor <memory>. Include <memory> before the import.

• GCC 16 with C++26 reflection: the 2026-03-22 snapshot of GCC 16 rejects an importer that includes <string> when -freflection is on ("conflicting imported declaration"), even with a module that has nothing to do with RTXUI. RTXUI turns reflection on when the compiler has it, so on that compiler, use the headers.