[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH] System V Shared memory interface
From: |
Neal H Walfield |
Subject: |
Re: [PATCH] System V Shared memory interface |
Date: |
Sat, 2 Jun 2001 16:19:22 -0500 |
User-agent: |
Mutt/1.2.5i |
> You seem to think I ever read a spec. Can you point me to one?
For starters, there is the single unix specification. As for
interpretations of SVIPC, look in Stevens' ``Advanced Programming in the
UNIX Environment'', Gay's ``Advanced UNIX Programming'' and `info ipc'
> I have not read anything that clearly defines shm identifiers. Can you
> cite why you think these identifiers are considered global things that you
> can communicate to other processes?
>From chapter 22 of Gay:
Accessing by IPC ID
When the IPC ID for a resource is known, the resource can be
accessed directly. Unlike files, which must be opened, IPC
resources can be accessed immediately when the IPC ID is known.
The one exception to this rule is that shared memory must be
attached to your process memory space before it can be
referenced (see shmat(2)).
> (I mean, then, what's the "key" for?)
The key is one way of communciating to other processes how to find the
identifier.