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.\" ========================================================================
.\"
.IX Title "xpa n"
.TH xpa n "April 14, 2011" "version 2.1.13" "SAORD Documentation"
.SH "NAME"
\&\fBXPA: Public Access to Data and Algorithms\fR
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
This document is the Table of Contents for \s-1XPA\s0.
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The \s-1XPA\s0 messaging system provides seamless communication between many
kinds of Unix programs, including X programs and Tcl/Tk programs.  It
also provides an easy way for users to communicate with XPA-enabled
programs by executing \s-1XPA\s0 client commands in the shell or by utilizing
such commands in scripts.  Because \s-1XPA\s0 works both at the programming
level and the shell level, it is a powerful tool for unifying any
analysis environment: users and programmers have great flexibility in
choosing the best level or levels at which to access \s-1XPA\s0 services, and
client access can be extended or modified easily at any time.
.PP
A program becomes an XPA-enabled server by defining named points of
public access through which data and commands can be exchanged with
other client programs (and users).  Using standard \s-1TCP\s0 sockets as a
transport mechanism, \s-1XPA\s0 supports both single-point and broadcast
messaging to and from these servers.  It supports direct communication
between clients and servers, or indirect communication via an
intermediate message bus emulation program. Host-based access control
is implemented, as is as the ability to communicate with \s-1XPA\s0 servers
across a network.
.PP
\&\s-1XPA\s0 implements a layered interface that is designed to be useful both
to software developers and to users.  The interface consists of a
library of \s-1XPA\s0 client and server routines for use in C/\*(C+ programs and
a suite of high-level user programs built on top of these libraries.
Using the \s-1XPA\s0 library, access points can be added to Tcl/Tk programs,
Xt programs, or to Unix programs that use the \s-1XPA\s0 event loop or any
event loop based on \fIselect()\fR.  Client access subroutines can be added
to any Tcl/Tk, Xt, or Unix program. Client access also is supported at
the command line via a suite of high-level programs.
.PP
Choose from the following topics:
.IP "\(bu" 4
Introduction to \s-1XPA\s0
[xpaintro(n)]
.IP "\(bu" 4
Access Point Names and Templates
[xpatemplate(n)]
.IP "\(bu" 4
Getting Common Information About Access Points
[xpacommon(n)]
.IP "\(bu" 4
Communication Methods
[xpamethod(n)]
.IP "\(bu" 4
Communication Between Hosts
[xpainet(n)]
.IP "\(bu" 4
Distinguishing Users
[xpausers(n)]
.IP "\(bu" 4
\&\s-1XPA\s0 User Programs
.RS 4
.IP "\(bu" 4
xpaget: get data and info
[\fIxpaget\fR\|(1)]
.IP "\(bu" 4
xpaset: send data and info
[\fIxpaset\fR\|(1)]
.IP "\(bu" 4
xpainfo: send info alert
[\fIxpainfo\fR\|(1)]
.IP "\(bu" 4
xpaaccess: get access point info
[\fIxpaaccess\fR\|(1)]
.IP "\(bu" 4
xpamb: message bus emulation
[\fIxpamb\fR\|(1)]
.IP "\(bu" 4
xpans: the \s-1XPA\s0 name server
[\fIxpans\fR\|(1)]
.RE
.RS 4
.RE
.IP "\(bu" 4
\&\s-1XPA\s0 Server Routines
.RS 4
.IP "\(bu" 4
XPANew: define a new access point
[\fIxpanew\fR\|(3)]
.IP "\(bu" 4
XPACmdNew: define a new command access point
[\fIxpacmdnew\fR\|(3)]
.IP "\(bu" 4
XPACmdAdd: add a command
[\fIxpacmdadd\fR\|(3)]
.IP "\(bu" 4
XPACmdDel: delete a command
[\fIxpacmddel\fR\|(3)]
.IP "\(bu" 4
XPAInfoNew: define an info access point
[\fIxpainfonew\fR\|(3)]
.IP "\(bu" 4
XPAFree: free an access point
[\fIxpafree\fR\|(3)]
.IP "\(bu" 4
XPAMainLoop: event loop for select server
[\fIxpamainloop\fR\|(3)]
.IP "\(bu" 4
XPAPoll: poll for \s-1XPA\s0 events
[\fIxpapoll\fR\|(3)]
.IP "\(bu" 4
XPACleanup: release reserved \s-1XPA\s0 memory
[\fIxpacleanup\fR\|(3)]
.IP "\(bu" 4
\&\s-1XPA\s0 Server Macros: accessing structure internals
[\fIxpamacros\fR\|(3)]
.IP "\(bu" 4
\&\s-1XPA\s0 Race Conditions: how to avoid them
[\fIxparace\fR\|(3)]
.IP "\(bu" 4
\&\s-1XPA\s0 Out of Memory (\s-1OOM\s0) errors
[\fIxpaoom\fR\|(3)]
.RE
.RS 4
.RE
.IP "\(bu" 4
\&\s-1XPA\s0 Client Routines
.RS 4
.IP "\(bu" 4
XPAOpen: open a persistent client connection
[\fIxpaopen\fR\|(3)]
.IP "\(bu" 4
XPAClose: close persistent client connection
[\fIxpaclose\fR\|(3)]
.IP "\(bu" 4
XPAGet: get data
[\fIxpaget\fR\|(3)]
.IP "\(bu" 4
XPASet: send data or commands
[\fIxpaset\fR\|(3)]
.IP "\(bu" 4
XPAInfo: send an info alert
[\fIxpainfo\fR\|(3)]
.IP "\(bu" 4
XPAGetFd: get data and write to an fd
[\fIxpagetfd\fR\|(3)]
.IP "\(bu" 4
XPASetFd: read data from and fd and send
[\fIxpasetfd\fR\|(3)]
.IP "\(bu" 4
XPANSLookup: look up an access point
[\fIxpanslookup\fR\|(3)]
.IP "\(bu" 4
XPAAccess: get access info
[\fIxpaaccess\fR\|(3)]
.IP "\(bu" 4
The XPA/Xt Interface: Xt interface to \s-1XPA\s0
[xpaxt(n)]
.IP "\(bu" 4
The XPA/Tcl Interface: Tcl interface to \s-1XPA\s0
[xpatcl(n)]
.RE
.RS 4
.RE
.IP "\(bu" 4
Tailoring the \s-1XPA\s0 Environment
.RS 4
.IP "\(bu" 4
Environment Variables
[xpaenv(n)]
.IP "\(bu" 4
Access Control
[xpaacl(n)]
.RE
.RS 4
.RE
.IP "\(bu" 4
Miscellaneous
.RS 4
.IP "\(bu" 4
Where to Find Example/Test Code
.IP "\(bu" 4
User Changes Between \s-1XPA\s0 1.0 and 2.0
.IP "\(bu" 4
\&\s-1API\s0 Changes Between \s-1XPA\s0 1.0 and 2.0
.IP "\(bu" 4
What Does \s-1XPA\s0 Stand For, Anyway?
.RE
.RS 4
.RE
