>> Actually, his implementation is similar to ringbuffer.c in >> libjack... and assumes that reading and writing can happen >> atomically (as was pointed out by someone else) -- which can >> be managed with single reader / single writer >> requirement.[a] >> Unless I've misunderstood the code, ringbuffer.c is /not/ >> using special atomic operations. > > Why should a single-reader-single-writer ring-buffer need atomic operations? > > The reader increments the read-pointer (which doesn't have to be a pointer) > last when its finished,
how do you ensure, that the read pointer is incremented _after_ the data has been written to the output? > the writer increments the write-pointer last when it > has written. likewise, how do you ensure, that the write pointer is incremented _after_ the data has been written to the ringbuffer? also, when reading the read/write pointers, you need to ensure, that they are loaded, before you touch the ringbuffer. > All other access is read-only. No problems. (At least in my app.) your code may work on x86, not necessarily on ppc, ia64 ... and then there is alpha ... we are not in a world, where assembler instructions are executed one after the other, but we have out-of-order cpus with speculation and multi-processor systems with non-shared caches ... hth, tim -- t...@klingt.org http://tim.klingt.org Which is more musical, a truck passing by a factory or a truck passing by a music school? John Cage
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