NIO CommKit Host Interface Installation and System Administration Manual

6-8

Porting CommKit Applications To Release 4.x

Programmer-Level Compatibility

NOTE: The TTY devices in the /dev/dkt directory are used for accounting purposes

only and only provide a TTY interface for incoming calls accepted by the dkserver

process.

Message Boundaries

This release of the CommKit software preserves message boundaries as they

are received from the network. This means that all incoming URP GOS1 and

GOS2 data is available immediately and all URP GOS5 (that is, block

mode) data is available after the appropriate veriﬁcation and processing. The

block mode message boundaries are preserved with the following

exceptions:

• Messages are split at every level-D URP code. (Refer to read(2) in the System

Call Compatibility section later in this chapter.)

• Messages may not be larger than 10240 bytes. Messages received that are larger

than this value are split into two or more smaller messages at boundaries

convenient to the dkhs driver.

Header Files

This section describes the header ﬁles that you need when you write

applications that operate with the CommKit software. The support for the

contents of these ﬁles is limited to the #deﬁne entries and the structures and

global variables listed on the library manual pages. Table 6-5 contains

descriptions of the header ﬁles you may need.

Table 6-2 CommKit Software Header Files

Header File Description

dk.h The dk.h ﬁle contains the error codes, external declarations,

and default ﬁle names used by the CommKit software.

Include dk.h in any application that places calls.

dk_urp.h The dk_urp.h ﬁle contains the URP level-D codes used by the

dkeveld library function.

rdfp.h The rdfp.h ﬁle contains the dk_lvld_t deﬁnition used by the

dkleveld library function.