SCO OpenServer

emajor(D3oddi)

emajor, eminor -- extract extended major/minor device numbers

Synopsis

#include <sys/sysmacros.h>

int emajor(dev_t dev);

int eminor(dev_t dev);

Description

The emajor macro returns the external (real) major device numbers associated with device type, dev.

The eminor macro returns the external (real) minor device numbers associated with device type, dev.

Arguments

dev: device number of type dev_t that contains both the major and minor device numbers.

Return values

emajor returns the external major device number, while eminor returns the external minor device number.

Usage

The major(D3oddi), makedev(D3oddi), and minor(D3oddi) functions support extended minor device numbers (minor numbers greater than 255). The base major device number and extended minor device number for a device have a one-to-one correspondence with the real (external) major and minor device numbers (defined in mdevice(F)). This effectively removes the former limit on the number of devices that a device driver can allocate to an adapter.

The -M option to configure(ADM) allows you to state the maximum and minimum number of devices that can be specified in the sdevice(F) file; and, using the -X option, is the command used to add or delete extended minor device numbers from the mdevice file.

Context and synchronization

All contexts.

Hardware applicability

All

Version applicability

oddi: 3, 3mp, 4, 4mp, 5, 5mp, 6, 6mp

SVR5 DDI compatibility

DDI drivers do not support these functions. For DDI versions prior to version 8, use the getemajor(D3) function in place of emajor( ) and the geteminor(D3) function in place of eminor( ).

DDI 8 and later versions use the channel and instance number rather than major and minor numbers. See ``Channel number'' in HDK Technical Reference, ``Device instance'' in HDK Technical Reference, and ``Device number'' in HDK Technical Reference for more information.

References

configure(ADM) major(D3oddi), makedev(D3oddi), mdevice(F) , minor(D3oddi), sdevice(F)

``Major and minor numbers'' in HDK Technical Reference