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CHAPTER 23
Endpoint Interface
About the Endpoint Interface 23-5
The different types of data forms and the defaults are described in more detail in
“Data Form Symbols” (Table 20-1 on page 20-2) in Newton Programmer’s
Reference.
Only a subset of data form values is applicable for any particular operation.
Table 23-1 enumerates the data forms and their applicability to output specs, input
specs, and endpoint option frames.
Template Data Form 23
The 'template data form enables you to pass data as if you were passing C
structures, and is thus extremely useful in communicating with the lower level
communication tools in getting and setting endpoint options.
When you set options or send data using the
'template data form, the data is
expected to be a frame containing two slots,
arglist and typelist. The
arglist slot is an array containing the data, the list of arguments. The typelist
slot is a corresponding array containing the types that describe the data.
To get endpoint options, the data in the
data slot must be a frame containing the
arglist and typelist arrays. The arglist array should contain placeholder
or default values. The system supplies the actual
arglist values when the option
list is returned.
In the same manner, to receive data, you must add a
target slot to your input
spec containing the
arglist and typelist arrays. The arglist array contains
Table 23-1 Data form applicability
Data form Output spec Input spec Option frame
'char
default for characters OK OK
'number
default for numbers OK OK
'string
default for strings default OK
'bytes
OK OK OK
'binary
default for binary objects;
output spec can include
optional
target slot
OK; input spec
must include
target slot
OK
'template
OK OK; input spec
must include
target slot
default
'frame
OK OK not applicable
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