How can I detect memory leaks in QtCreator on Windows? On the doc, they recommend Memcheck but it only works on Mac and Linux. Any suggestion for Windows?
After many tries I finally found a method to detect the memory leaks of a Qt project on Windows:
1) First, it cannot be done directly in Qt Creator so you need to create a Visual C++ project to do the memory leak detection. Thankfully, qmake makes this easy. Open the Qt SDK command line tool and run:
qmake -spec win32-msvc2008 -tp vc
This will convert your project to a .vcproj.
2) Open this project and add the necessary code for memory leak detection:
To your main.cpp file:
// Necessary includes and defines for memory leak detection:
#ifdef _MSC_VER
#define _CRTDBG_MAP_ALLOC
#include <crtdbg.h>
#endif // _MSC_VER
#if defined(_MSC_VER)
// Code to display the memory leak report
// We use a custom report hook to filter out Qt's own memory leaks
// Credit to Andreas Schmidts - http://www.schmidt-web-berlin.de/winfig/blog/?p=154
_CRT_REPORT_HOOK prevHook;
int customReportHook(int /* reportType */, char* message, int* /* returnValue */) {
// This function is called several times for each memory leak.
// Each time a part of the error message is supplied.
// This holds number of subsequent detail messages after
// a leak was reported
const int numFollowupDebugMsgParts = 2;
static bool ignoreMessage = false;
static int debugMsgPartsCount = 0;
// check if the memory leak reporting starts
if ((strncmp(message,"Detected memory leaks!\n", 10) == 0)
|| ignoreMessage)
{
// check if the memory leak reporting ends
if (strncmp(message,"Object dump complete.\n", 10) == 0)
{
_CrtSetReportHook(prevHook);
ignoreMessage = false;
} else
ignoreMessage = true;
// something from our own code?
if(strstr(message, ".cpp") == NULL)
{
if(debugMsgPartsCount++ < numFollowupDebugMsgParts)
// give it back to _CrtDbgReport() to be printed to the console
return FALSE;
else
return TRUE; // ignore it
} else
{
debugMsgPartsCount = 0;
// give it back to _CrtDbgReport() to be printed to the console
return FALSE;
}
} else
// give it back to _CrtDbgReport() to be printed to the console
return FALSE;
}
#endif
int main(int argc, char *argv[]) {
#if defined(_MSC_VER)
_CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF);
prevHook = _CrtSetReportHook(customReportHook);
// _CrtSetBreakAlloc(157); // Use this line to break at the nth memory allocation
#endif
QApplication* app = new QApplication(argc, argv);
int appError = app->exec();
delete app;
#if defined(_MSC_VER)
// Once the app has finished running and has been deleted,
// we run this command to view the memory leaks:
_CrtDumpMemoryLeaks();
#endif
return appError;
}
3) With this, your project should now be able to detect memory leaks. Note the _MSC_VER
defines so that this code is only executed when your run it from Visual C++ (not from Qt Creator). It means you can still do the development with Qt Creator and just re-run step 1 whenever you need to check for memory leaks.
4) To break at a particular memory allocation, use _CrtSetBreakAlloc()
More information memory leak detection on Microsoft's website: http://msdn.microsoft.com/en-us/library/e5ewb1h3%28v=vs.80%29.aspx