passing by reference... my darkest enemy
actual reason below:
In your case (without reference) the compiler generates a temporary object (int) for the first argument of your MyApplication constructor. You pass this temporary int to QApplication’s constructor (with int reference), which saves the address of this reference. Once your MyApplication constructor is done the temporary int is destroyed but QApplication still has its address.
/* This file is NOT open source. See "license.txt" to read the full license provided with the Xfire SDK. */
#ifndef __XFIREGAMECLIENT_H__
#define __XFIREGAMECLIENT_H__
#ifdef __cplusplus
extern "C" {
#endif
/*
** XfireIsLoaded()
**
** returns 1 if application can talk to Xfire, 0 otherwise
*/
int XfireIsLoaded();
/*
** XfireSetCustomGameDataA()
**
** ANSI version to tell xfire of custom game data
*/
int XfireSetCustomGameDataA(int num_keys, const char **keys, const char **values);
/*
** XfireSetCustomGameDataA()
**
** UNICODE version to tell xfire of custom game data
*/
int XfireSetCustomGameDataW(int num_keys, const wchar_t **keys, const wchar_t **values);
/*
** XfireSetCustomGameDataUTF8()
**
** UTF8 version to tell xfire of custom game data
*/
int XfireSetCustomGameDataUTF8(int num_keys, const char **keys, const char **values);
#ifdef UNICODE
#define XfireSetCustomGameData XfireSetCustomGameDataW
#else
#define XfireSetCustomGameData XfireSetCustomGameDataA
#endif
#ifdef __cplusplus
}
#endif
#endif /* __XFIREGAMECLIENT_H__ */