About This Guide

For an overview of the changes to the software and docs, see ``What's new in TCP/IP 4.25'' below.

The Programmer's Guide is intended for developers who wish to use the socket programming interface to create TCP/IP-based applications on QNX.

Throughout this guide, we assume that the QNX TCP/IP Development Toolkit has been installed on your system.

This guide contains the following chapters:

Socket Programming in QNX - describes how to generate socket-based applications.
A Socket-based IPC Tutorial - contains an introduction to Interprocess Communication (IPC) and a general discussion of sockets.
An Advanced Socket Communication Tutorial - describes further details of socket-based communications.
Remote Procedure Call Programming - provides an overview of RPC and describes how to generate RPC applications.
Writing Data Server Applications - describes how to use the data server to share state information among processes.
TCP/IP Libraries - socket-programming functions, data structures, and key protocols, arranged alphabetically.

You'll also find an appendix describing the client side of the SOCKS firewall package.

You should note that the socket-programming functions described in these chapters are implementations of traditional UNIX-style network IPC developed by the University of California, Berkeley. This socket-programming interface provides an alternative to the IPC native to QNX.

If your application doesn't require TCP/IP (e.g. it runs within the QNX LAN environment and portability isn't an issue), you should consider using the native QNX IPC facilities. The QNX IPC facilities use less overhead in your application, so your program will run faster. To learn more about QNX IPC, see the QNX System Architecture book.

Credits

The tutorial chapters in this guide are adapted from the following:

Stuart Sechrest,
An Introductory Socket Communication Tutorial,
Computer Science Research Group Computer Science Division,
Department of Electrical Engineering and Computer Science,
University of California, Berkeley

S.J. Leffler, R.S. Fabry, W.N. Joy, P. Lapsley, S. Miller, & C. Torek, 1986,
An Advanced 4.3 BSD Interprocess Communication Tutorial,
Computer Systems Research Group,
Department of Electrical Engineering and Computer Science,
University of California, Berkeley

What's new in TCP/IP 4.25

New functionality
New content in the docs
Corrections

New functionality

Slinger webserver
SNMP version 2
DHCP client
Enhanced support for bootp
Support for lookup keyword in /etc/resolv.conf
Updated BIND package (named, named-xfer, nslookup)
Shared libraries

New content in the docs

Writing Data Server Applications chapter
A list of the TCP/IP libraries, arranged by category.
Data server functions:
- ds_clear() -delete a data server variable.
- ds_create() -create a data server variable.
- ds_deregister() -deregister your application with the data server.
- ds_flags() -set the flags for a data server variable.
- ds_get() -retrieve a data server variable.
- ds_register() -register your application with the data server.
- ds_set() -set a data server variable.
SNMP data types and functions:
- read_main_config_file() -read the snmpd.conf file.
- snmp_pdu - structure that describes an SNMP transaction.
- snmp_pdu_create() - create an SNMP message structure.
- snmp_session - structure that defines a set of transactions with similar transport characteristics.

Corrections

A Socket-based IPC Tutorial: The tut4.c, tut5.c, and tut6.c examples have been corrected. You can find the source for the examples in the /usr/demo/src/socket directory.
Remote Procedure Call Programming: RPC programs must be compiled with the -Wc,ei option to cc (or the -ei option to wcc386).
gethostname(): Include <unix.h> to use this function.
rcmd(): The prototype has been corrected. Include <unix.h> to use this function.
res_query(): This function returns the length of a reply message, in bytes, or -1 if an error occurs.
res_search(): This function returns the length of a reply message, in bytes, or -1 if an error occurs.
rresvport(): Include <resolv.h> to use this function.
sethostname(): Include <unix.h> to use this function.
socketpair(): The list of errors has been corrected.
SOCKSinit(): This function returns 1 (not -1) if an error occurs.

The prototype has been corrected for the following functions: