Win32: Fix using executable instance and not ours

Operations that take an instance handle should be passed the handle of whatever module we are inside instead of blindly passing the handle of the executable. This commit makes GLFW retrieve its own instance on initialization. This makes the most difference for window classes, which are per-instance. Using the executable instance led to name conflicts if there were several copies of GLFW in a single process. Note that having this is still a bad idea unless you know what things to avoid, and those things are mostly platform-specific. This is partly because the library wasn't designed for it and partly because it needs to save, update and restore various per-process and per-session settings like current context and video mode. However, multiple simultaneous copies of GLFW in a single Win32 process should now at least initialize, like is already the case on other platforms. Fixes glfw#469 Fixes glfw#1296 Fixes glfw#1395 Related to glfw#927 Related to glfw#1885
g-martin772 · Mar 17, 2022 · 07a5518 · 07a5518
1 parent 66a4882
commit 07a5518
Showing 6 changed files with 20 additions and 6 deletions.
diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
@@ -90,6 +90,7 @@ video tutorials.
  - IntellectualKitty
  - Aaron Jacobs
  - Erik S. V. Jansson
+ - jjYBdx4IL
  - Toni Jovanoski
  - Arseny Kapoulkine
  - Cem Karan
@@ -210,6 +211,7 @@ video tutorials.
  - Jared Tiala
  - Sergey Tikhomirov
  - Arthur Tombs
+ - TronicLabs
  - Ioannis Tsakpinis
  - Samuli Tuomola
  - Matthew Turner

diff --git a/README.md b/README.md
@@ -214,6 +214,7 @@ information on what to include when reporting a bug.
    scancode than `PrtSc` (#1993)
  - [Win32] Bugfix: `GLFW_KEY_PAUSE` scancode from `glfwGetKeyScancode` did not
    match event scancode (#1993)
+ - [Win32] Bugfix: Instance-local operations used executable instance (#469,#1296,#1395)
  - [Cocoa] Added support for `VK_EXT_metal_surface` (#1619)
  - [Cocoa] Added locating the Vulkan loader at runtime in an application bundle
  - [Cocoa] Moved main menu creation to GLFW initialization time (#1649)

diff --git a/src/win32_init.c b/src/win32_init.c
@@ -71,6 +71,16 @@ BOOL WINAPI DllMain(HINSTANCE instance, DWORD reason, LPVOID reserved)
 //
 static GLFWbool loadLibraries(void)
 {
+    if (!GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
+                                GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
+                            (const WCHAR*) &_glfw,
+                            (HMODULE*) &_glfw.win32.instance))
+    {
+        _glfwInputErrorWin32(GLFW_PLATFORM_ERROR,
+                             "Win32: Failed to retrieve own module handle");
+        return GLFW_FALSE;
+    }
+
     _glfw.win32.user32.instance = _glfwPlatformLoadModule("user32.dll");
     if (!_glfw.win32.user32.instance)
     {
@@ -334,7 +344,7 @@ static GLFWbool createHelperWindow(void)
                         WS_CLIPSIBLINGS | WS_CLIPCHILDREN,
                         0, 0, 1, 1,
                         NULL, NULL,
-                        GetModuleHandleW(NULL),
+                        _glfw.win32.instance,
                         NULL);
 
     if (!_glfw.win32.helperWindowHandle)

diff --git a/src/win32_joystick.c b/src/win32_joystick.c
@@ -574,7 +574,7 @@ GLFWbool _glfwInitJoysticksWin32(void)
 {
     if (_glfw.win32.dinput8.instance)
     {
-        if (FAILED(DirectInput8Create(GetModuleHandleW(NULL),
+        if (FAILED(DirectInput8Create(_glfw.win32.instance,
                                       DIRECTINPUT_VERSION,
                                       &IID_IDirectInput8W,
                                       (void**) &_glfw.win32.dinput8.api,

diff --git a/src/win32_platform.h b/src/win32_platform.h
@@ -442,6 +442,7 @@ typedef struct _GLFWwindowWin32
 //
 typedef struct _GLFWlibraryWin32
 {
+    HINSTANCE           instance;
     HWND                helperWindowHandle;
     HDEVNOTIFY          deviceNotificationHandle;
     int                 acquiredMonitorCount;

diff --git a/src/win32_window.c b/src/win32_window.c
@@ -1321,7 +1321,7 @@ static int createNativeWindow(_GLFWwindow* window,
                                            fullWidth, fullHeight,
                                            NULL, // No parent window
                                            NULL, // No window menu
-                                           GetModuleHandleW(NULL),
+                                           _glfw.win32.instance,
                                            (LPVOID) wndconfig);
 
     _glfw_free(wideTitle);
@@ -1429,7 +1429,7 @@ GLFWbool _glfwRegisterWindowClassWin32(void)
     wc.cbSize        = sizeof(wc);
     wc.style         = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
     wc.lpfnWndProc   = (WNDPROC) windowProc;
-    wc.hInstance     = GetModuleHandleW(NULL);
+    wc.hInstance     = _glfw.win32.instance;
     wc.hCursor       = LoadCursorW(NULL, IDC_ARROW);
     wc.lpszClassName = _GLFW_WNDCLASSNAME;
 
@@ -1459,7 +1459,7 @@ GLFWbool _glfwRegisterWindowClassWin32(void)
 //
 void _glfwUnregisterWindowClassWin32(void)
 {
-    UnregisterClassW(_GLFW_WNDCLASSNAME, GetModuleHandleW(NULL));
+    UnregisterClassW(_GLFW_WNDCLASSNAME, _glfw.win32.instance);
 }
 
 int _glfwCreateWindowWin32(_GLFWwindow* window,
@@ -2447,7 +2447,7 @@ VkResult _glfwCreateWindowSurfaceWin32(VkInstance instance,
 
     memset(&sci, 0, sizeof(sci));
     sci.sType = VK_STRUCTURE_TYPE_WIN32_SURFACE_CREATE_INFO_KHR;
-    sci.hinstance = GetModuleHandleW(NULL);
+    sci.hinstance = _glfw.win32.instance;
     sci.hwnd = window->win32.handle;
 
     err = vkCreateWin32SurfaceKHR(instance, &sci, allocator, surface);