NODEV is not a part of Posix, but it is defined as (dev_t)-1 on many systems (in particularly, on Linux, FreeBSD, NetBSD, OpenBSD, OpenIndiana). It is used to denote non-existing or undefined value for dev_t values.
On Linux, FreeBSD and OpenIndiana major(NODEV), minor(NODEV) and makedev(NODEV, NODEV) return NODEV. Unfortunately, this is not so on NetBSD and OpenBSD, but anyway it can be useful.
Linked PRs
NODEVis not a part of Posix, but it is defined as(dev_t)-1on many systems (in particularly, on Linux, FreeBSD, NetBSD, OpenBSD, OpenIndiana). It is used to denote non-existing or undefined value fordev_tvalues.On Linux, FreeBSD and OpenIndiana
major(NODEV),minor(NODEV)andmakedev(NODEV, NODEV)returnNODEV. Unfortunately, this is not so on NetBSD and OpenBSD, but anyway it can be useful.Linked PRs