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Inside Macintosh: Networking /

Chapter 11 - Ethernet, Token Ring, and Fiber Distributed Data Interface / Ethernet, Token Ring, and FDDI Reference

Routines / Writing and Reading Ethernet Packets

ERdCancel

The ERdCancel function cancels execution of a specific call to the ERead function.

FUNCTION ERdCancel (thePBptr: EParamBlkPtr; 
                     async: Boolean): OSErr;

thePBptr

A pointer to a parameter block of type EParamBlock.

async

A Boolean value that specifies whether the function should be
executed asynchronously or synchronously. Specify TRUE for asynchronous execution.

-->	ioCompletion	ProcPtr	A pointer to completion routine.
<--	ioResult	OSErr	The result code.
-->	ioRefNum	Integer	The driver reference number.
-->	csCode	Integer	Always ENetRdCancel for this function.
-->	ePointer	Ptr	A pointer to ERead parameter block.

Field Description

ePointer

A pointer to the .ENET parameter block that you specified when you called the ERead function that you want to cancel.

DESCRIPTION

To cancel an ERead function request using the ERdCancel function, you must have called the ERead function asynchronously. You specify in the ePointer parameter a pointer to the parameter block that you used when you called the ERead function.

When you call the ERdCancel function, the pending ERead function that you cancel receives the reqAborted result code.

TOKEN RING AND FDDI CONSIDERATIONS

This function is not valid for token ring and FDDI.

ASSEMBLY-LANGUAGE INFORMATION

To execute the ERdCancel function from assembly language, call the _Control
trap macro with a value of ENetRdCancel in the csCode field of the parameter
block. To execute the _Control trap asynchronously, include the value ,ASYNC in
the operand field.

RESULT CODES

noErr	0	No error
cbNotFound	-1102	ERead not active