Inside Macintosh: Networking With Open Transport / Part 1 - Open Transport Essentials

Chapter 6 - Mappers

This chapter describes mappers, a type of Open Transport provider that lets your application map entity names to protocol addresses. You can use mapper functions to register a name, to look up a name or name pattern, or to remove
a registered name. Which functions are supported depends on the name-
registration protocol underlying the mapper provider you create. For more detailed information about how mapper functions are implemented for
the protocol you are interested in, consult the documentation provided for
that protocol.

You do not have to open a mapper provider if you are interested only in registering a name or looking up an address corresponding to a name.

• If the protocol you are using allows you to bind an endpoint by name and you do so, the name is automatically registered on the network. This is a more efficient way to register a name on the network than to create a mapper to do it.

• If you want to obtain the address that corresponds to an entity name, you can use the endpoint function OTResolveAddress. Using this function also saves you the trouble of opening a mapper. However, you cannot use this function to look up a name pattern; that is, the name you look up cannot include a wildcard character.

• If you want to connect to a remote endpoint simply by specifying its name, you can simply pass the name to the OTConnect function.

If you are using an endpoint that cannot be bound by name, if you want to look up a name pattern, if you want to register a name that is not associated with an endpoint, or if you want to use other mapper functions, you need to read this chapter and learn how to create a mapper provider.

This chapter begins with a general description of mapper providers and continues with a more detailed discussion of how you use mappers asynchronously and how you use the mapper to look up names. The functions used to register names and delete names are discussed in "Mappers Reference".

Mapper providers, like all Open Transport providers, can operate synchronously or asynchronously and can block. For general information about Open Transport providers, see the chapter "Providers".

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Chapter Contents

About Mappers

Using Mappers

Setting Modes of Operation for Mappers

Specifying Name and Address Information

Searching for Names

Retrieving Entries in Asynchronous Mode

Code Sample: Using OTLookupName