Ben Boeckel <me@xxxxxxxxxxxxxx> wrote: > > One loss message. I set a flag on the last slot in the pipe ring to say that > > message loss occurred, but there's insufficient space to store a counter > > without making the slot larger (and I really don't want to do that). > > > > Note that every slot in the pipe ring has such a flag, so you could, > > theoretically, get a loss message after every normal message that you read > > out. > > Ah, so a "you lost something" is just a flag on the next event that does > make it into the queue? I read it as a whole message existed indicating > that data was lost. Not sure of the best wording here. No. That flag is internal. It causes read() to fabricate a message and insert it into the user buffer after the flagged message has been copied over. > > bit 0 is 2^0 in this case. I'm not sure how better to describe it. > > OK, so the bits are in native-endian order in the enclosing bytes. But C > just doesn't have a set ABI for bitfields (AFAIK), so I guess it's > "whatever GCC does" in practice? Hard to say - powerpc and s390 have bit 0 as the MSB:-/ But "& (1 << 0)" gets you 2^0, whatever the CPU book says. David
