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Chapter 3 - Endpoints / Endpoints Reference

Constants and Data Types

The TEndpointInfo Structure

The TEndpointInfo structure describes the initial characteristics of an endpoint that you opened by calling the OTOpenEndpoint function (page 3-82) or the OTAsyncOpenEndpoint function (page 3-76). These functions return as a parameter a pointer to a TEndpointInfo structure, if there is one. The TEndpointInfo structure is optional; some endpoints might not provide one, depending on which protocol modules they use. You can also obtain a pointer to the TEndpointInfo structure by calling the OTGetEndpointInfo function (page 3-82) or the OTBind function (page 3-77).

You use the TEndpointInfo structure to find out how large a buffer you must allocate to send or receive information for the endpoint and what kind of services the endpoint provides.

IMPORTANT

It is recommended that you do not hard-code TEndpointInfo field values into your application when specifying the maximum length of buffers because these values might change.

The TEndpointInfo structure is defined by the TEndpointInfo data type.

struct TEndpointInfo
{
   SInt32   addr;       /* maximum size of an address */
   SInt32   options;    /* maximum size of options */
   SInt32   tsdu;       /* normal data transmit unit size*/
   SInt32   etsdu;      /* expedited data transmit unit size */
   SInt32   connect;    /* maximum data size on connect */
   SInt32   discon;     /* maximum data size on disconnect */
   UInt32   servtype;   /* service type */
   UInt32   flags;      /* flags  */
};
typedef struct TEndpointInfo TEndpointInfo;

Field Description

addr

A value greater than 0 indicates the maximum size (in bytes) of a protocol address to which you can bind this endpoint. A value of T_INVALID indicates that this endpoint does not allow access to protocol addresses; it is being used for serial communication.

options

A value greater than 0 indicates the maximum number of bytes needed to store the protocol-specific options that this endpoint supports, if any. A value of T_INVALID indicates that this endpoint has no protocol-specific options that you can set.

tsdu

For a transactionless endpoint, a positive value indicates the maximum number of bytes in a transport service data unit (TSDU) for this endpoint. A value of T_INFINITE indicates that there is no limit to the size of a TSDU. A value of 0 indicates that the provider does not support the concept of a TSDU. This means that you can send a data stream with no logical boundaries preserved across a connection. A value of T_INVALID indicates that this endpoint cannot transfer normal data (as opposed to expedited data).

For a transaction-based endpoint, this field indicates the maximum number of bytes in a response.

etsdu

For a transactionless endpoint, a positive value indicates the maximum number of bytes in an expedited transport service data unit (ETSDU) for this endpoint. A value of T_INFINITE indicates that there is no limit to the size of a ETSDU. A value of 0 indicates that this endpoint does not support the concept of an ETSDU. This means that you can send an expedited data stream with no logical boundaries preserved across a connection. A value of T_INVALID indicates that this endpoint cannot transfer expedited data.

For a transaction-based endpoint, this field indicates the maximum number of bytes in a request.

connect

For a connection-oriented endpoint, a value greater than 0 indicates the maximum amount of data (in bytes) that you can send with the OTSnd function (page 3-130) or OTAccept function (page 3-127). A value of T_INVALID indicates that this endpoint does not let you send data with these functions. This field is meaningless for other types of endpoints.

discon

For a connection-oriented endpoint, a value greater than 0 indicates the maximum amount of data (in bytes) that you can send using the OTSndDisconnect function (page 3-149) and the OTSndOrderlyDisconnect function (page 3-153). A value of T_INVALID indicates that this endpoint does not let you send data with these functions. This field is meaningless for other types of endpoints.

servtype

A constant that indicates what kind of service the endpoint provides. Possible values are given by the endpoint service enumeration (page 3-44).

flags

A bit field that provides additional information about the endpoint. Possible values are given by the endpoint flags enumeration (page 3-45).