sqInt clipboardSize(void) {
extern int forceInterruptCheck(void);
/* return the number of characters in the clipboard entry */
if (!sqHasClipboard) {
/* if squeak doesn't have the clipboard, we need to
* fetch the clipboard contents from the current holder
*/
fetchClipboard();
forceInterruptCheck();
}
return strlen(clipboardBuffer);
}
/* Signal the external semaphore with the given index. Answer non-zero on
* success, zero otherwise. This function is (should be) thread-safe;
* multiple threads may attempt to signal the same semaphore without error.
* An index of zero should be and is silently ignored.
*
* (sig) As well as negative index.
*/
sqInt
signalSemaphoreWithIndex(sqInt index)
{
int next;
/* An index of zero should be and is silently ignored. */
if (index <=0)
return 0;
/* we must use the locking semantics to avoid ABA problem on writing a semaphore index to queue,
so there is no chance for fetching thread to observe queue in inconsistent state.
*/
lockSignalQueue();
/* check for queue overflow */
next = succIndex(sigIndexHigh);
if (next == sigIndexLow ) {
#if SQ_DYNAMIC_QUEUE_SIZE
// grow and retry
unlockSignalQueue();
ioGrowSignalQueue( maxPendingSignals + 100);
return signalSemaphoreWithIndex(index);
#else
unlockSignalQueue();
// error if queue size is static (perhaps better would be to sleep for a while and retry?)
error("External semaphore signal queue overflow");
#endif
}
signalQueue[sigIndexHigh] = index;
/* make sure semaphore index is written before we advance sigIndexHigh */
sqLowLevelMFence();
sigIndexHigh = next;
/* reset lock */
unlockSignalQueue();
forceInterruptCheck();
return 1;
}
