.\" $NetBSD: makedev.3,v 1.2 2011/04/01 06:03:06 jruoho Exp $
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.\" Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
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.\" $FreeBSD: src/share/man/man3/makedev.3,v 1.2 2008/09/28 20:26:16 ed Exp $
.\"
.Dd April 1, 2011
.Dt MAKEDEV 3
.Os
.Sh NAME
.Nm makedev ,
.Nm major ,
.Nm minor
.Nd device number conversion
.Sh SYNOPSIS
.In sys/types.h
.Ft dev_t
.Fn makedev "int major" "int minor"
.Ft int
.Fn major "dev_t dev"
.Ft int
.Fn minor "dev_t dev"
.Sh DESCRIPTION
The
.Fn makedev
macro allows a unique device number to be generated based on its
.Fa major
and
.Fa minor
number.
The
.Fn major
and
.Fn minor
macros can be used to obtain the original numbers from the device number
.Fa dev .
.Pp
All block and character devices are uniquely
identified by a pair of major and minor numbers.
The major number refers to a certain device class (e.g. disks, TTYs)
while the minor number identifies an instance within the device class.
.Sh RETURN VALUES
The
.Fn major
macro returns a device major number that has a value between 0 and 255.
The
.Fn minor
macro returns a device minor number whose value can span the complete
range of an
.Vt int .
.Sh SEE ALSO
.Xr mknod 2 ,
.Xr devname 3 ,
.Xr MAKEDEV 8