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AIX Version 4.3 Kernel and Subsystems Technical Reference, Volume 2

tokselect Token-Ring Device Handler Entry Point


Determines whether a specified event has occurred on the token-ring device.


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


devno Specifies major and minor device numbers.
events Specifies the conditions to check, denoted by the bitwise OR of one or more of the following:
POLLIN Check whether receive data is available.
POLLOUT Check whether transmit available.
POLLPRI Check whether status is available.
POLLSYNC Check whether asynchronous notification is available.
reventp Points to the result of condition checks. A bitwise OR one of the following conditions is returned:
POLLIN Indicates available receive data.
POLLOUT Indicates available transmit.
POLLPRI Indicates available status.
chan Specifies the channel number assigned by the tokmpx entry point.


Note: Only user-mode callers should call this entry point.

The tokselect entry point is called when the select or poll subroutine is used to determine if a specified event has occurred on the token-ring device.

When the token-ring device handler is in a state in which the event can never be satisfied (for example, an adapter failure), then the tokselect entry point sets the returned events flags to 1 for the event that cannot be satisfied. This prevents the select or poll subroutines from waiting indefinitely.

Execution Environment

The tokselect entry point can only be called from the process environment.

Return Values

ENXIO Indicates the specified minor number is not valid.
EACCES Indicates a call from a kernel process is not valid.

Implementation Specifics

The tokselect entry point functions with a Token-Ring High Performance Network Adapter that has been correctly configured for use on a qualified network. Consult adapter specifications for more information on configuring the adapter and network qualifications.

Related Information

The poll subroutine, select subroutine.

Select/Poll Logic for ddwrite and ddread Routines.

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