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AIX Version 4.3 Kernel and Subsystems Technical Reference, Volume 2

entmpx Ethernet Device Handler Entry Point


Allocates and deallocates a channel for an Ethernet device handler.


#include <sys/device.h>
int entmpx (devno, chanp, channame)
dev_t devno;
int *chanp;
char *channame;


devno Specifies the major and minor device numbers.
chanp Contains the channel ID passed as a reference parameter. If the channame parameter is null, this parameter is the channel ID to be deallocated. Otherwise, the chanp parameter is set to the ID of the allocated channel.
channame Points to the remaining path name describing the channel to allocate. The channame parameter accepts the following values:
null Deallocates the channel.
Pointer to a null string Allows a normal open sequence of the Ethernet device on the channel ID generated by the entmpx entry point.
Pointer to a "D" Allows the Ethernet device to be opened in Diagnostic mode on the channel ID generated by the entmpx entry point.


The entmpx entry point allocates and deallocates a channel for an Ethernet device handler. This entry point is not called directly by a user. The kernel calls the entmpx entry point in response to an open or close request.

Note: If the Ethernet device has been successfully opened, any subsequent Diagnostic mode open requests is unsuccessful. If the device has been successfully opened in Diagnostic mode, all subsequent open requests is unsuccessful.

Execution Environment

An entmpx 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 entmpx entry point are the following:

EBUSY Indicates the maximum number of opens was exceeded.
ENOMSG No message of desired type.
ENODEV Indicates the specified device does not exist.
ENXIO Indicates the device is not configured.

Implementation Specifics

The entmpx 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 entopen entry point.

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