User`s guide

3: FMP DLI Functions

DC 900-1339H 37

• You can specify ICP link parameters in the DLI ASCII conﬁguration ﬁle and then

run the

dlicfg preprocessor program (see Chapter 5). The dlOpen function uses

the resulting DLI binary conﬁguration ﬁle to perform the link conﬁguration dur-

ing the DLI session establishment process.

• You can perform ICP link conﬁguration within the client application (described

in Section 3.4.1.4). This method is useful if you need to change link conﬁguration

without exiting the application.

3.1.2 Normal versus Raw Operation

There are two choices for the protocol DLI conﬁguration parameter:

• A session is opened for Normal operation if you set protocol to a speciﬁc protocol

(for example,

“FMP”); then the DLI software conﬁgures the ICP links using the

values in the DLI conﬁguration ﬁle and transparently handles all headers and I/O.

• A session is opened for Raw operation if you set protocol to “raw”; then your

application must handle all conﬁguration, headers, and I/O details. Refer to the

Freeway Data Link Interface Reference Guide if you need to use Raw operation.

To read and write using Normal operation, your client application typically interacts

with Freeway only for the purpose of exchanging data with the remote application. The

writeType DLI configuration parameter (Table 5–1 on page 104) specifies the type of

data (normal or transparent).

However, if your client application needs to interact with Freeway to obtain status or

reports, or to provide Freeway with protocol-speciﬁc information relating to the data

exchange, Normal and Raw operation can be mixed. The client application session

should be conﬁgured for Normal operation (allowing DLI to handle some of the head-

ers), but the write and read requests (Section 3.4 and Section 3.5) can use Raw opera-

tion by including the optional arguments structure (Section 3.3) containing the

protocol-speciﬁc information.