STREAMS modules and driver development

This topic provides information about implementing STREAMS modules and drivers on SVR5 and SCO OpenServer 5 systems. Readers who need a general introduction to the STREAMS interface should read STREAMS Modules and Drivers: UNIX SVR 4.2, published by Prentice-Hall, 1992.

The manual pages for the STREAMS interface cover both the SVR5 and SCO OpenServer 5 interfaces and are in the following sections:

Section D2str manual pages -- STREAMS entry point routines
Section D3str manual pages -- STREAMS kernel functions
Section D4str manual pages -- STREAMS structures
Section D7str manual pages -- STREAMS message types
Section D4flpi manual pages -- DLPI structures
Section D7dlpi manual pages -- DLPI message types
Section D7tpi manual pages -- TPI message types

Message types

Intro(D7str) lists all the STREAMS message types that are supported for SVR5 and identifies those that are not also supported on SCO OpenServer 5 Release 5. Individual pages in that section provide detailed compatibility notes for that message.

STREAMS does not prevent a module or driver from generating any message type and sending it in any direction on the Stream. However, established processing and direction rules should be observed. Stream head processing according to message type is fixed, although certain parameters can be altered.

Loadable STREAMS modules

General information about using Dynamically Loadable Kernel Modules (DLKM) is in ``Dynamically-loadable kernel modules (DLKM)''.

Developing a STREAMS driver or module entails:

taking advantage of style guidelines, which describe advanced features and performance enhancements
enabling driver installation and configuration
testing and debugging the driver
adding TPI extensions (if appropriate)

If you are porting an SCO OpenServer 5 or SVR5 1 or 2 STREAMS driver to SVR5, see ``STREAMS in DDI 8''.