On 28-04-08 12:44, ?? wrote:
I got a problem here: I have a large share memory (say, 1.5GB) to be mapped into several processes' address space, I wanna make sure that the addresses those processes use to map the shared memory are a same one according to some reason. Specifically speaking, I will invoke shmat () in every process with a same second argument, a same address. But there is possibility that some times in some processes I can not make sure that the address is not in use. So my question is: what address should I choose, is there anything about process memory management in UNIX standards (posix, xopen...). I can make sure that I will attatch the shared memory right after the process starts.
Not that I'm aware of and I quite doubt anything useful exists. Are you on 32 or 64-bit? On 32-bit 1.5G is pretty large, on 64 it should be peanuts.
Anyways, usually, even when not guaranteed anything, you'd expect to be able to in practice get the same address. I know recent Red Hat distributions use addressspace randomization which easily could interfere. I suppose you are using Debian:
`- Debian GNU/Linux - The power of freedom
(ugh) and I do not know if it also does. Does it? I'll do you a favour and not ask why on earth you'd want the same address. Rene. -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
