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CHAPTER 23

Endpoint Interface

23-12 Using the Endpoint Interface

Receiving Data Using Input Specs 23

The most common way to receive data is to use input specs. An input spec is a

frame that deﬁnes what kind of data you are looking for, termination conditions

that control when the input should be stopped, and callback methods to notify you

when input is stopped or other conditions occur.

An input spec consists of many pieces. It contains slots that deﬁne

■ the type of data expected (form slot)

■ the input target for template and binary data (target slot)

■ the data termination conditions (termination slot)

■ protocol ﬂags for receiving data (rcvFlags slot)

■ an inactivity time-out (reqTimeout slot)

■ the data ﬁlter options (filter slot)

■ the options associated with the receive request (rcvOptions slot)

■ a method to be called when the termination conditions are met

(

InputScript method)

■ a method to be called periodically to check input as it accumulates

(

PartialScript method, partialFrequency slot)

■ a method to be called if the input spec terminates unexpectedly

(

CompletionScript method)

Table 23-2 summarizes the various input data forms and the input spec slots that

are applicable to them. Input spec slots not included in the table apply to all data

forms. For more details on the input spec frame, see “Input Spec Frame”

(page 20-11) in Newton Programmer’s Reference.

After you’ve connected or accepted a connection, you set up your ﬁrst input spec

by calling

SetInputSpec. When one input spec terminates, the system

automatically posts another input spec for you when the

InputScript method

deﬁned in the previous input spec returns. This new input spec duplicates the

one that just terminated. If you don’t want this to happen, you can call the

SetInputSpec method from within the InputScript method of your input

spec to change the input spec or terminate the input. Pass

nil to SetInputSpec

to terminate the input.

You also use the

SetInputSpec method if you need to set up an input spec at

some other point. Note that if you want to terminate a current input spec to set up a

new one, you must call the

Cancel method before calling SetInputSpec with

your new spec. (This applies inside an

InputScript that is called as a result of

calling the

Input method.)

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