ok@quintus.UUCP (Richard A. O'Keefe) (12/28/89)
When you perform an ioctl, there are at least two "objects" which may be affected. In effect, a file descriptor is a handle for a "working" object which keeps track of things like file position, access rights requested and granted, locks, and so on. This "working" object may itself refer in some way to an "external" object such as a disc, serial port, tape drive, and so on. Some ioctls obviously refer to the working object, e.g. FIOCLEX, I_PUSH. Some obviously refer to the external object, e.g. MTIOCTOP. There are quite a few where I don't find it obvious, especially in the terminal interfaces (BSD, SysV, POSIX). What I'd _like_ to understand is what happens when someone has several descriptors for connections to the same (physical or pseudo) terminal. Which properties of an fd connected to a terminal can I trust not to be changed behind my back through another fd?
brnstnd@stealth.acf.nyu.edu (01/05/90)
In article <1295@quintus.UUCP> ok@quintus.UUCP (Richard A. O'Keefe) writes: > Which properties of an fd > connected to a terminal can I trust not to be changed behind my back > through another fd? None. ---Dan