Technical Note NW09

RegisterName

CONTENTS Introduction References Downloadables

[Feb 01 1989]

Introduction

The verify flag indicator byte (verifyFlag) of the AppleTalk RegisterName function should always be set TRUE in published code.


The AppleTalk chapter of Inside Macintosh, Volume II-322, in describing the RegisterName function, states:

"If verifyFlag is TRUE, RegisterName checks on the network to see if the name is already in use, and returns a result code of nbpDuplicate if so."

Note that verifyFlag should always be TRUE in published code. The design of the Name Binding Protocol (NBP) requires that an entity name be unique. The way RegisterName ensures this uniqueness is by broadcasting a lookup request for the registered name. If any entity responds, then RegisterName knows that the name would not be unique and returns an error. Some developers, in anticipating the time delay involved in broadcasting a lookup request and waiting for a response, have opted to set verifyFlag to FALSE, not realizing the potential danger in doing so.

Apple provides verifyFlag for experimental or developmental purposes, such as narrowing down a problem in registering a name on a network. Always make sure that code which ships has verifyFlag set to TRUE.

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References

Inside Macintosh, Volume II-261, The AppleTalk Manager

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Downloadables

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