condition variable on read/write locks

Hello. I have the following problem: I have one writter and many readers. The writter writes in a buffer and the readers read from this buffer. It's not classicle producer/consumers, because all the readers need to read all the data that the writter has written. I implemented it using read/write lock: Write lock for writting and read lock for reading. The problem is that when there's no data to be read I must use busywait or sleepwait. If condition variables worked with read/write locks it would be easy: Every write sygnals, if the reader has read all the data it blocks on condition variable... but no, there isn't condition variable for read/write locks. So my question is: Is there any way to avoid sleepwait with some mechanism given the situation? I must not use mutexes, because there are many many readers. Thanks

Why not use Events? Check out CEvent, and the win32 equivalent. Your threads can block on an event without using a lot of CPU and be awakend by some master when it chooses.

I use the posix standart. What is this library with the events? I've never heard of it.

>> The problem is that when there's no data to be read I must use busywait or sleepwait
When writers have nothing to write, keep the write-lock acquired. This will keep the readers efficiently blocked while there's nothing to read.

gg