Re^8: need a thread to wait until a buffer is full.

They aren't signals in that sense of the word. In the sense of cond_signal().

Basically, the thread in waiting on cond_wait() will not be allocated any timeslices by the scheduler until the other thread calls cond_signal() (or broadcast). So, no polling a second shared var to see if the first is ready yet.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

"Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."

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Re^9: need a thread to wait until a buffer is full. by zentara (Cardinal) on Jul 26, 2007 at 12:57 UTC
I'll have to look into that, but if the thread waits (without any timeslices) for the cond_signal from the other thread, that would limit it to watching only 1 thread. The way I envisioned it, the controlling thread could ask many other threads to fill their buffers simultaneously, and then go into a loop to harvest them as they come in, and still do other things as well, like asking for more buffer-filling. I'm not really a human, but I play one on earth. Cogito ergo sum a bum	[reply]
Re^10: need a thread to wait until a buffer is full. by BrowserUk (Patriarch) on Jul 26, 2007 at 13:30 UTC
but if the thread waits (without any timeslices) for the cond_signal from the other thread, that would limit it to watching only 1 thread. No, that is not so. The variable upon which the `cond_wait()` is waiting can be `cond_signal()`ed from any thread (that has a lock on the variable). Also, if more than one thread are in a `cond_wait()` state on the same variable, one of them (non-determanistically) will be awoken. You can also signal a variable using `cond_broadcast()`, in which case all threads currently blocking on that variable will be woken up, rather than just one. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply] [d/l] [select]