dlcclose Entry Point of the GDLC Device Manager

Communications Technical Reference, Volume 1

dlcclose Entry Point of the GDLC Device Manager

Purpose

Closes a generic data link control (GDLC) channel.

Syntax

#include <sys/device.h>

int dlcclose (devno, chan, ext)
dev_t devno;
int chan, ext;

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

Description

The dlcclose entry point is called when a user's application program invokes the close subroutine or when a kernel user calls the fp_close kernel service. This routine disables a GDLC channel for the user. If this is the last channel to close on the port, the GDLC device manager issues a close to the network device handler and deletes the kernel process that serviced device handler events on behalf of the user.

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. There is one dev_t device number for each type of GDLC, such as Ethernet, Token-Ring, or SDLC.
chan	Specifies the channel ID assigned by GDLC in the dlcmpx routine at open time.
ext	Specifies the extended subroutine parameter. This parameter is ignored by GDLC.

Return Values

0	Indicates a successful operation.
EBADF	Indicates a bad file number. This value is defined in the /usr/include/sys/errno.h file.

Implementation Specifics

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

Related Information

The close subroutine.

The ddclose device entry point.

The dlcmpx entry point of the GDLC device manager, dlcopen entry point of the GDLC device manager.

The fp_close kernel service.

Generic Data Link Control (GDLC) Environment Overview in AIX Version 4.3 Communications Programming Concepts.