Merge f983f0a4f7 into 994915dbb9

* Add the umbrella module ftxui to the cmake module build.

* Update cpp20 modules documentation.

cmake/ftxui_modules.cmake

@@ -6,6 +6,7 @@ add_library(ftxui-modules)
 
 target_sources(ftxui-modules
   PUBLIC FILE_SET CXX_MODULES FILES
+  src/ftxui/ftxui.cppm
   src/ftxui/component.cppm
   src/ftxui/component/animation.cppm
   src/ftxui/component/captured_mouse.cppm

doc/cpp20-modules.md

@@ -12,8 +12,24 @@ FTXUI experimentally supports
 compilation times and improve code organization. Each header has a
 corresponding module.
 
-**Example with CMake and Ninja**
+Use the FTXUI_BUILD_MODULES option to build the FTXUI project itself to provide C++ 20 modules,
+for example with CMake and Ninja:
 
+```sh
+cmake \
+    -DCMAKE_GENERATOR=Ninja \
+    -DFTXUI_BUILD_MODULES=ON \
+    ..
+
+ninja
+```
+
+> [!NOTE]
+> To use modules, you need a C++20 compatible compiler, CMake version 3.20 or
+> higher, and use a compatible generator like Ninja. Note that Makefile
+> generators **do not support modules**.
+
+Then, in your own code you can consume the modules and code as normal:
 
 ```cpp
 import ftxui;
@@ -26,23 +42,30 @@ int main() {
 }
 ```
 
-```sh
-cmake \
-    -DCMAKE_GENERATOR=Ninja \
-    -DFTXUI_BUILD_MODULES=ON \
-    ..
+Note, the `ftxui` convenience module which simply pulls together all the modules:
 
-ninja
+```cpp
+export import ftxui.component;
+export import ftxui.dom;
+export import ftxui.screen;
+export import ftxui.util;
+```
+You can instead import only the module(s) you need if desired.
+
+To properly find and link the modules with CMake, use `target_link_libraries` to get the right
+compiler, linker, etc. flags.
+
+```cmake
+target_link_libraries(my_executable
+    #...whatever...
+    PRIVATE ftxui::modules
+)
 ```
-> [!NOTE]
-> To use modules, you need a C++20 compatible compiler, CMake version 3.20 or
-> higher, and use a compatible generator like Ninja. Note that Makefile
-> generators **do not support modules**.
 
 ### Module list
 
 The modules directly reference the corresponding header, or a group of related
-headers to provide a more convenient interface. The following modules 
+headers to provide a more convenient interface. The following modules
 are available:
 
 - `ftxui`

src/ftxui/component/screen_interactive.cpp

@@ -1022,23 +1022,23 @@ void ScreenInteractive::Signal(int signal) {
 
 void ScreenInteractive::FetchTerminalEvents() {
 #if defined(_WIN32)
-  auto get_input_records = [&] {
+  auto get_input_records = [&] () -> std::vector<INPUT_RECORD> {
     // Check if there is input in the console.
     auto console = GetStdHandle(STD_INPUT_HANDLE);
     DWORD number_of_events = 0;
     if (!GetNumberOfConsoleInputEvents(console, &number_of_events)) {
-      return;
+      return std::vector<INPUT_RECORD>();
     }
     if (number_of_events <= 0) {
       // No input, return.
-      return;
+      return std::vector<INPUT_RECORD>();
     }
     // Read the input events.
     std::vector<INPUT_RECORD> records(number_of_events);
     DWORD number_of_events_read = 0;
     if (!ReadConsoleInput(console, records.data(), (DWORD)records.size(),
                           &number_of_events_read)) {
-      return;
+      return std::vector<INPUT_RECORD>();
     }
     records.resize(number_of_events_read);
     return records;