NAME
makedev, major,
minor —
create or extract device
numbers
SYNOPSIS
#include
<sys/types.h>
dev_t
makedev(unsigned
int maj, unsigned int
min);
unsigned int
major(dev_t
dev);
unsigned int
minor(dev_t
dev);
DESCRIPTION
On OpenBSD, all devices on the system are assigned a unique number which consists of a major and minor component. Typically, the major number identifies the kind of device and the minor number identifies a specific instance of the device.
The
makedev()
macro is used to combine a major and minor device number into a form
suitable for use with the mknod(2) system call.
The
major() macro
extracts the major number from the specified device number.
The
minor() macro
extracts the minor number from the specified device number.
RETURN VALUES
The makedev() macro returns a combined
device number from the specified major and minor numbers.
The major() macro returns the major number
corresponding to the specified device number.
The minor() macro returns the minor number
corresponding to the specified device number.
SEE ALSO
STANDARDS
The makedev(),
major(), and minor() macros
are not standardized by IEEE Std 1003.1
(“POSIX.1”) but are available on most systems.
HISTORY
The makedev(),
major(), and minor() macros
first appeared in Version 7 AT&T
UNIX.
CAVEATS
On some systems, makedev(),
major(), and minor() are
implemented as functions rather than macros.