Backends: Win32: Clarify how the WndProc handler requires a forward declaration.

examples/example_win32_directx10/main.cpp

@@ -207,8 +207,10 @@ void CleanupRenderTarget()
     if (g_mainRenderTargetView) { g_mainRenderTargetView->Release(); g_mainRenderTargetView = NULL; }
 }
 
+// Forward declare message handler from imgui_impl_win32.cpp
+extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
+
 // Win32 message handler
-extern LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
 LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
 {
     if (ImGui_ImplWin32_WndProcHandler(hWnd, msg, wParam, lParam))

examples/example_win32_directx11/main.cpp

@@ -211,8 +211,10 @@ void CleanupRenderTarget()
     if (g_mainRenderTargetView) { g_mainRenderTargetView->Release(); g_mainRenderTargetView = NULL; }
 }
 
+// Forward declare message handler from imgui_impl_win32.cpp
+extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
+
 // Win32 message handler
-extern LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
 LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
 {
     if (ImGui_ImplWin32_WndProcHandler(hWnd, msg, wParam, lParam))

examples/example_win32_directx12/main.cpp

@@ -427,8 +427,10 @@ void ResizeSwapChain(HWND hWnd, int width, int height)
     assert(g_hSwapChainWaitableObject != NULL);
 }
 
+// Forward declare message handler from imgui_impl_win32.cpp
+extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
+
 // Win32 message handler
-extern LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
 LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
 {
     if (ImGui_ImplWin32_WndProcHandler(hWnd, msg, wParam, lParam))

examples/example_win32_directx9/main.cpp

@@ -202,8 +202,10 @@ void ResetDevice()
     ImGui_ImplDX9_CreateDeviceObjects();
 }
 
+// Forward declare message handler from imgui_impl_win32.cpp
+extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
+
 // Win32 message handler
-extern LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
 LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
 {
     if (ImGui_ImplWin32_WndProcHandler(hWnd, msg, wParam, lParam))

examples/imgui_impl_win32.cpp

@@ -2,7 +2,7 @@
 // This needs to be used along with a Renderer (e.g. DirectX11, OpenGL3, Vulkan..)
 
 // Implemented features:
-//  [X] Platform: Clipboard support (for Win32 this is actually part of core imgui)
+//  [X] Platform: Clipboard support (for Win32 this is actually part of core dear imgui)
 //  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
 //  [X] Platform: Keyboard arrays indexed using VK_* Virtual Key Codes, e.g. ImGui::IsKeyPressed(VK_SPACE).
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
@@ -255,13 +255,18 @@ void    ImGui_ImplWin32_NewFrame()
 #define DBT_DEVNODES_CHANGED 0x0007
 #endif
 
-// Process Win32 mouse/keyboard inputs.
-// You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
+// Win32 message handler (process Win32 mouse/keyboard inputs, etc.)
+// Call from your application's message handler.
+// When implementing your own back-end, you can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if Dear ImGui wants to use your inputs.
 // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application.
 // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application.
-// Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
+// Generally you may always pass all inputs to Dear ImGui, and hide them from your application based on those two flags.
 // PS: In this Win32 handler, we use the capture API (GetCapture/SetCapture/ReleaseCapture) to be able to read mouse coordinates when dragging mouse outside of our window bounds.
 // PS: We treat DBLCLK messages as regular mouse down messages, so this code will work on windows classes that have the CS_DBLCLKS flag set. Our own example app code doesn't set this flag.
+#if 0
+// Copy this line into your .cpp file to forward declare the function.
+extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
+#endif
 IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 {
     if (ImGui::GetCurrentContext() == NULL)

examples/imgui_impl_win32.h

@@ -2,7 +2,7 @@
 // This needs to be used along with a Renderer (e.g. DirectX11, OpenGL3, Vulkan..)
 
 // Implemented features:
-//  [X] Platform: Clipboard support (for Win32 this is actually part of core imgui)
+//  [X] Platform: Clipboard support (for Win32 this is actually part of core dear imgui)
 //  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
 //  [X] Platform: Keyboard arrays indexed using VK_* Virtual Key Codes, e.g. ImGui::IsKeyPressed(VK_SPACE).
 //  [X] Platform: Gamepad support. Enabled with 'io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad'.
@@ -17,9 +17,9 @@ IMGUI_IMPL_API void     ImGui_ImplWin32_NewFrame();
 //#define IMGUI_IMPL_WIN32_DISABLE_GAMEPAD
 //#define IMGUI_IMPL_WIN32_DISABLE_LINKING_XINPUT
 
-// Handler for Win32 messages, update mouse/keyboard data.
-// You may or not need this for your implementation, but it can serve as reference for handling inputs.
-// Intentionally commented out to avoid dragging dependencies on <windows.h> types. You can COPY this line into your .cpp code instead.
+// Win32 message handler
+// - Intentionally commented out in a '#if 0' block to avoid dragging dependencies on <windows.h>
+// - You can COPY this line into your .cpp code to forward declare the function.
 #if 0
-IMGUI_IMPL_API LRESULT  ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
+extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
 #endif