static int winMutex_isInit = 0;
static int winMutex_isNt = -1; /* <0 means "need to query" */

/* As the winMutexInit() and winMutexEnd() functions are called as part
** of the sqlite3_initialize() and sqlite3_shutdown() processing, the
** "interlocked" magic used here is probably not strictly necessary.
*/
static LONG volatile winMutex_lock = 0;
static LONG SQLITE_WIN32_VOLATILE winMutex_lock = 0;

int sqlite3_win32_is_nt(void); /* os_win.c */
void sqlite3_win32_sleep(DWORD milliseconds); /* os_win.c */

static int winMutexInit(void){
  /* The first to increment to 1 does actual initialization */
  if( InterlockedCompareExchange(&winMutex_lock, 1, 0)==0 ){

** 1:   Operating system is Win9x.
** 2:   Operating system is WinNT.
**
** In order to facilitate testing on a WinNT system, the test fixture
** can manually set this value to 1 to emulate Win98 behavior.
*/
#ifdef SQLITE_TEST
LONG volatile sqlite3_os_type = 0;
LONG SQLITE_WIN32_VOLATILE sqlite3_os_type = 0;
#else
static LONG volatile sqlite3_os_type = 0;
static LONG SQLITE_WIN32_VOLATILE sqlite3_os_type = 0;
#endif

#ifndef SYSCALL
#  define SYSCALL sqlite3_syscall_ptr
#endif

/*

#if defined(InterlockedCompareExchange)
  { "InterlockedCompareExchange", (SYSCALL)0,                    0 },

#define osInterlockedCompareExchange InterlockedCompareExchange
#else
  { "InterlockedCompareExchange", (SYSCALL)InterlockedCompareExchange, 0 },

#define osInterlockedCompareExchange ((LONG(WINAPI*)(LONG volatile*, \
        LONG,LONG))aSyscall[76].pCurrent)
#define osInterlockedCompareExchange ((LONG(WINAPI*)(LONG \
        SQLITE_WIN32_VOLATILE*, LONG,LONG))aSyscall[76].pCurrent)
#endif /* defined(InterlockedCompareExchange) */

}; /* End of the overrideable system calls */

/*
** This is the xSetSystemCall() method of sqlite3_vfs for all of the
** "win32" VFSes.  Return SQLITE_OK opon successfully updating the

** Determine if we are dealing with WinRT, which provides only a subset of
** the full Win32 API.
*/
#if !defined(SQLITE_OS_WINRT)
# define SQLITE_OS_WINRT 0
#endif

/*
** For WinCE, some API function parameters do not appear to be declared as
** volatile.
*/
#if SQLITE_OS_WINCE
# define SQLITE_WIN32_VOLATILE
#else
# define SQLITE_WIN32_VOLATILE volatile
#endif

#endif /* _OS_WIN_H_ */