make QElapsedTimer use QSystemLibrary on win

we also need to ensure the counterFrequency was already set up,
thus volatile (which fixes possible race condition)

Merge-request: 2655
Reviewed-by: Jan-Arve Saether <jan-arve.saether@nokia.com>

1 files changed, 6 insertions, 8 deletions

diff --git a/src/corelib/tools/qelapsedtimer_win.cpp b/src/corelib/tools/qelapsedtimer_win.cpp
index d79dc5d..e6bce27 100644
--- a/src/corelib/tools/qelapsedtimer_win.cpp
+++ b/src/corelib/tools/qelapsedtimer_win.cpp
@@ -42,6 +42,8 @@
 #include "qelapsedtimer.h"
 #include <windows.h>
 
+#include <private/qsystemlibrary_p.h>
+
 typedef ULONGLONG (WINAPI *PtrGetTickCount64)(void);
 static PtrGetTickCount64 ptrGetTickCount64 = 0;
 
@@ -52,21 +54,17 @@ static quint64 counterFrequency = 0;
 
 static void resolveLibs()
 {
-    static bool done = false;
+    static volatile bool done = false;
     if (done)
         return;
 
     // try to get GetTickCount64 from the system
-    HMODULE kernel32 = GetModuleHandleW(L"kernel32");
-    if (!kernel32)
+    QSystemLibrary kernel32(QLatin1String("kernel32"));
+    if (!kernel32.load())
         return;
 
-#if defined(Q_OS_WINCE)
     // does this function exist on WinCE, or will ever exist?
-    ptrGetTickCount64 = (PtrGetTickCount64)GetProcAddress(kernel32, L"GetTickCount64");
-#else
-    ptrGetTickCount64 = (PtrGetTickCount64)GetProcAddress(kernel32, "GetTickCount64");
-#endif
+    ptrGetTickCount64 = (PtrGetTickCount64)kernel32.resolve("GetTickCount64");
 
     // Retrieve the number of high-resolution performance counter ticks per second
     LARGE_INTEGER frequency;