From a63ca3fa106f4b0f9776bf2004661ef6dec2c0c6 Mon Sep 17 00:00:00 2001
From: Thiago Macieira <thiago.macieira@intel.com>
Date: Thu, 28 Apr 2016 14:09:32 -0700
Subject: Implement QLibrary::PreventUnloadHint for Windows

It's interesting that the HMODULE/HINSTANCE pointer points to something
in the actual module that got loaded, so we can use its value as
"address of something in the module" for GetModuleHandleEx. The "PIN"
flag tells the Windows DLL loader to never unload.

Change-Id: Ifea6e497f11a461db432ffff1449a2169eb6293e
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Kai Koehne <kai.koehne@qt.io>
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>
---
 src/corelib/plugin/qlibrary_win.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'src/corelib/plugin/qlibrary_win.cpp')

diff --git a/src/corelib/plugin/qlibrary_win.cpp b/src/corelib/plugin/qlibrary_win.cpp
index deec54db0a..95e5afa837 100644
--- a/src/corelib/plugin/qlibrary_win.cpp
+++ b/src/corelib/plugin/qlibrary_win.cpp
@@ -148,6 +148,16 @@ bool QLibraryPrivate::load_sys()
         else
             qualifiedFileName = dir.filePath(moduleFileName);
 #endif // !Q_OS_WINRT
+
+        if (loadHints() & QLibrary::PreventUnloadHint) {
+            // prevent the unloading of this component
+            HMODULE hmod;
+            bool ok = GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_PIN |
+                                        GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
+                                        reinterpret_cast<const wchar_t *>(pHnd),
+                                        &hmod);
+            Q_ASSERT(!ok || hmod == pHnd);
+        }
     }
     return (pHnd != 0);
 }
-- 
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