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AIX Version 4.3 Kernel and Subsystems Technical Reference, Volume 2

entselect Ethernet Device Handler Entry Point

Purpose

Determines whether a specified event has occurred on the Ethernet device.

Syntax

#include <sys/device.h>
#include <sys/comio.h>
int entselect (devno, events, reventp, chan)
dev_t devno;
ushort events;
ushort *reventp;
int chan;

Parameters

devno Specifies major and minor device numbers.
events Identifies the events to check.
reventp Returned events pointer passed by reference. This pointer is used by the entselect entry point to indicate which of the selected events are true when the call occurs.
chan Specifies the channel number assigned by the entmpx entry point.

Description

Note: Only user-mode callers should use the entselect entry point.

The entselect entry point determines if a specified event has occurred on the Ethernet device. This entry point must be called with the select or poll subroutine.

When the Ethernet device handler is in a state in which the specified event cannot be satisfied (for example, an adapter failure), then the entselect entry point sets the returned event flags to 1. This prevents the select or poll subroutine from waiting indefinitely.

Execution Environment

An entselect entry point can be called from the process environment only.

Return Values

In general, communication device handlers use the common return codes defined for an entry point. However, device handlers for specific communication devices may return device-specific codes. The common return codes for the entselect entry point are the following:

EACCES Indicates permission was denied because the device had not been initialized. Indicates that the Diagnostic mode open request was denied. Indicates permission was denied because the call is from a kernel-mode process.
ENXIO Indicates there was no such device. (Maximum number of adapters was exceeded.)
EBUSY Indicates the open request was denied because the device was already open in Diagnostic mode or because the adapter was busy.
ENODEV Indicates no such device exists.

Implementation Specifics

The entselect entry point functions with an Ethernet High-Performance LAN adapter that has been correctly configured for use on a qualified network. Consult the adapter specifications for more information on configuring the adapter and network qualifications.

Related Information

The CIO_GET_FASTWRT ddioctl Communications PDH Operation, the entmpx entry point.

The poll subroutine, select subroutine.

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