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improved initialization

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This commit is contained in:
Jeff Hill
2000-04-28 01:00:43 +00:00
parent cb2904af5d
commit 0150adbbf7
1 changed files with 74 additions and 71 deletions
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145
src/libCom/osi/os/WIN32/osdTime.cpp
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@@ -101,82 +101,85 @@ static unsigned __stdcall osdTimeSynchThreadEntry (LPVOID)
static void osdTimeInit ()
{
LARGE_INTEGER parm;
BOOL win32Stat;
BOOL success;
int unixStyleStatus;
unsigned threadAddr;
unsigned long handle;
FILETIME epicsEpochFT;
DWORD status;
if ( osdTimeMutex ) {
/* wait for init to complete */
status = WaitForSingleObject ( osdTimeMutex, INFINITE );
assert ( status == WAIT_OBJECT_0 );
success = ReleaseMutex ( osdTimeMutex );
assert (success);
return;
}
else {
HANDLE osdTimeMutexTmp;
osdTimeMutexTmp = CreateMutex (NULL, TRUE, NULL);
if ( osdTimeMutexTmp == 0 ) {
return;
}
/* not supported on W95, but the alternative requires assuming that pointer and integer are the same */
if (InterlockedCompareExchange ( (PVOID *) &osdTimeMutex, (PVOID) osdTimeMutexTmp, (PVOID)0 ) != 0) {
CloseHandle (osdTimeMutexTmp);
/* wait for init to complete */
status = WaitForSingleObject (osdTimeMutex, INFINITE);
assert ( status == WAIT_OBJECT_0 );
success = ReleaseMutex (osdTimeMutex);
assert (success);
return;
}
}
//
// one time initialization of constants
// initialize elapsed time counters
//
if (!osdTimeMutex) {
unsigned threadAddr;
unsigned long handle;
FILETIME epicsEpochFT;
HANDLE mutex;
mutex = CreateMutex (NULL, TRUE, "osdTimeMutex");
if (mutex==NULL) {
return;
}
if ( GetLastError () == ERROR_ALREADY_EXISTS ) {
static const DWORD tmoTwentySec = 20 * osiTime::mSecPerSec;
DWORD semStatus;
//
// synchronize with some other thread
// that is already in this routine
//
semStatus = WaitForSingleObject (mutex, tmoTwentySec);
if ( semStatus == WAIT_OBJECT_0 ) {
ReleaseMutex (mutex);
}
return;
}
//
// initialize elapsed time counters
//
// All CPUs running win32 currently have HR
// counters (Intel and Mips processors do)
//
if (QueryPerformanceFrequency (&parm)==0) {
CloseHandle (mutex);
return;
}
perf_freq = parm.QuadPart;
//
// convert the EPICS epoch to file time
//
win32Stat = SystemTimeToFileTime (&epicsEpochST, &epicsEpochFT);
if (win32Stat==0) {
CloseHandle (mutex);
return;
}
parm.LowPart = epicsEpochFT.dwLowDateTime;
parm.HighPart = epicsEpochFT.dwHighDateTime;
epicsEpoch = parm.QuadPart;
osdTimeMutex = mutex;
ReleaseMutex (mutex);
unixStyleStatus = osdTimeSych ();
if (unixStyleStatus!=tsStampOK) {
osdTimeMutex = NULL;
CloseHandle (mutex);
return;
}
//
// spawn off a thread which periodically resynchronizes the offset
//
handle = _beginthreadex (NULL, 4096, osdTimeSynchThreadEntry,
0, 0, &threadAddr);
if (handle==NULL) {
errlogPrintf ("osdTimeInit(): unable to start time synch thread\n");;
}
atexit (osdTimeExit);
// All CPUs running win32 currently have HR
// counters (Intel and Mips processors do)
//
if ( QueryPerformanceFrequency (&parm) == 0 ) {
CloseHandle (osdTimeMutex);
osdTimeMutex = NULL;
return;
}
perf_freq = parm.QuadPart;
//
// convert the EPICS epoch to file time
//
success = SystemTimeToFileTime (&epicsEpochST, &epicsEpochFT);
if ( ! success ) {
CloseHandle ( osdTimeMutex );
osdTimeMutex = NULL;
return;
}
parm.LowPart = epicsEpochFT.dwLowDateTime;
parm.HighPart = epicsEpochFT.dwHighDateTime;
epicsEpoch = parm.QuadPart;
ReleaseMutex ( osdTimeMutex );
unixStyleStatus = osdTimeSych ();
if ( unixStyleStatus != tsStampOK ) {
CloseHandle ( osdTimeMutex );
osdTimeMutex = NULL;
return;
}
//
// spawn off a thread which periodically resynchronizes the offset
//
handle = _beginthreadex ( NULL, 4096, osdTimeSynchThreadEntry,
0, 0, &threadAddr );
if ( handle == NULL ) {
errlogPrintf ( "osdTimeInit(): unable to start time synch thread\n" );
}
atexit ( osdTimeExit );
}
//