Technical Reference: Communications, Volume 1

dlcconfig Entry Point of the GDLC Device Manager

Purpose

Configures the generic data link control (GDLC) device manager.

Syntax

#include <sys/uio.h>
#include <sys/device.h>

int dlcconfig ( devno, op, uiop)

Note: The dlc prefix is replaced with the three-digit prefix for the specific GDLC device manager being configured.

The dlcconfig entry point is called during the kernel startup procedures to initialize the GDLC device manager with its device information. The operating system also calls this routine when the GDLC is being terminated or queried for vital product data.

Parameters

devno	Indicates major and minor device numbers. This is a dev_t device number that specifies both the major and minor device numbers of the GDLC device manager. One dev_t device number exists for each type of GDLC, such as Ethernet, Token-Ring, or SDLC.
op	Specifies the operation code that indicates the function to be performed: CFG_INIT Initializes the GDLC device manager. CFG_TERM Terminates the GDLC device manager. CFG_QVPD Queries GDLC vital product data. This operation code is optional.
uiop	Points to the uio structure specifying the location and length of the caller's data area for the CFG_INIT and CFG_QVPD operation codes. No data areas are specifically defined for GDLC, but DLCs can define the data areas for a particular network.

Return Values

The following return values are defined in the /usr/include/sys/errno.h file:

0	Indicates a successful operation.
EINVAL	Indicates an invalid value.
ENODEV	Indicates that no such device handler is present.
EFAULT	Indicates that a kernel service, such as the uiomove or devswadd kernel service, has failed.

Implementation Specifics

Each GDLC supports the dlcconfig entry point as its switch table entry for the sysconfig subroutine. The file system calls this entry point from the process environment only.

Related Information

The ddconfig device entry point.

The uiomove kernel service.

Generic Data Link Control (GDLC) Environment Overview in AIX 5L Version 5.1 Communications Programming Concepts.