Beispiel #1
0
U_NAMESPACE_BEGIN

U_COMMON_API UBool U_EXPORT2 umtx_initImplPreInit(UInitOnce &uio) {
    for (;;) {
        int32_t previousState = InterlockedCompareExchange(
            (LONG volatile *) // this is the type given in the API doc for this function.
                &uio.fState,  //  Destination
            1,            //  Exchange Value
            0);           //  Compare value

        if (previousState == 0) {
            return true;   // Caller will next call the init function.
                           // Current state == 1.
        } else if (previousState == 2) {
            // Another thread already completed the initialization.
            //   We can simply return FALSE, indicating no
            //   further action is needed by the caller.
            return FALSE;
        } else {
            // Another thread is currently running the initialization.
            // Wait until it completes.
            do {
                Sleep(1);
                previousState = umtx_loadAcquire(uio.fState);
            } while (previousState == 1);
        }
    }
}
int32_t
SharedObject::getRefCount() const {
    return umtx_loadAcquire(refCount);
}