Quick Summary
=============

To build and install the XPA package, simply execute:

	./configure		# site-specific configuration
	make			# build the software
	make install		# install it
	make clean		# clean up unneeded temp files

We strongly recommend that you install in a directory other than the
default of /usr/local, so as not to require root access. To do this,
configure for a different install directory:

	./configure --prefix=<top_level_install_dir>
e.g.,
	./configure --prefix=/soft/saord

Programs will be installed in /soft/saord/bin, libraries in /soft/saord/lib,
include files in /soft/saord/include, and man pages in /soft/saord/man.
Indeed, we do this at SAO and recommend it as a general rule, in order
to keep SAORD software in one place that does not conflict with other
installations. Note that you will need to add the bin directory to
your path and the man directory to MANPATH.

The build ("make") takes only a minute or so on modern machines.  To
monitor its progress and/or check for errors, redirect output to a file
and use the 'tail' command:

	make >& foo.log &; tail -f foo.log		# csh
or
	make 1>foo.log 2>&1 &; tail -f foo.log		# sh, bash


Details of Installation
=======================

   NB: These are generic installation instructions, modified for XPA.

   The `configure' shell script attempts to guess correct values for
various system-dependent variables used during compilation.  It uses
those values to create a `Makefile' in each directory of the package.
It may also create one or more `.h' files containing system-dependent
definitions.  Finally, it creates a shell script `config.status' that
you can run in the future to recreate the current configuration, a file
`config.cache' that saves the results of its tests to speed up
reconfiguring, and a file `config.log' containing compiler output
(useful mainly for debugging `configure').

   If you need to do unusual things to compile the package, please try
to figure out how `configure' could check whether to do them, and mail
diffs or instructions to the address given in the `README' so they can
be considered for the next release.  If at some point `config.cache'
contains results you don't want to keep, you may remove or edit it.

   The file `configure.in' is used to create `configure' by a program
called `autoconf'.  You only need `configure.in' if you want to change
it or regenerate `configure' using a newer version of `autoconf'.

The simplest way to compile this package is:

     `./configure' to configure the package for your system.  If you're
     using `csh' on an old version of System V, you might need to type
     `sh ./configure' instead to prevent `csh' from trying to execute
     `configure' itself.

     Running `configure' takes awhile.  While running, it prints some
     messages telling which features it is checking for.

  1. `cd' to the directory containing the package's source code and type
    "./configure".  This runs a configuration script created by GNU
    autoconf, which configures XPA for your system and creates a
    Makefile.  The configure script allows you to customize the XPA
    configuration for your site; for details on how you can do this,
    type "./configure -help" or refer to the autoconf documentation (not
    included here). The XPA "configure" script supports the following special
    switch(es) in addition to the standard ones:

        --enable-shared=yes|link

				Build shared libraries in addition to the
				default static library. There are two options:

				If the value is "yes", shared libraries are
				built but not used to link xpa programs.

				If the value is "link", shared libraries are
				used to link xpa programs. If therefore becomes
				your responsibility to put the shared library
				where it can be found (or use LD_LIBRARY_PATH).

        --enable-threaded-xpans
				Build xpans to support separate threads for
				handling name server requests and xpa proxy
				callbacks. This is recommended if you are going
				to enable proxy handling in xpans (-P), since
				XPA long callbacks via proxy can interfere
				with the name server functions. (You still have
				to start xpans with -P 2 to use 2 threads.)

	--with-tcl=<dir>	
				Force build Tcl support using parameters found
				in <dir>/tclConfig.sh. Configure will look for
				the Tcl config script in standard places and
				will enable Tcl support if found. It will abort
				if tclConfig.sh points to a non-existent tcl.h
				file (some versions of Linux have shown this
				behavior). Use this switch to override the
				standard locations or to force a build even
				if tcl.h is not found (e.g. if you are going to
				install tcl as part of a larger build). With
				Tcl support enabled you can execute:

					make tclxpa

				to generate the XPA package as a shared Tcl
				object, loadable using Tcl "package require".
				Contact us with problems -- its been a bear to
				get this even half-way right.

	--with-threads
				If you are going to link XPA into a threaded
				program, you need to specify --with-threads.
				This add -D_REENTRANT to the compiler flags,
				which tells gcc to use thread-safe versions of
				global system variables such as errno. No code
				changes are made to XPA. Please note that all 
				XPA calls must be in a single thread: XPA is
				not thread-safe in and of itself but does work
				in threaded programs.

	--with-gtk=<include_dir>	
				Build with support for adding xpa to a gtk
				loop. The specified include directory must 
				contain the gtk directory which itself contains
				gtk.h, e.g.:

				    --with-gtk=/usr/local/include/gtk-1.2

				which contains gtk/gtk.h

    Standard options are listed below. the most important of which
    are --exec-prefix and --prefix (to specify where to install), and
    --x-includes=DIR and --x-libraries=DIR (for non-standard X installations).
    We recommend --prefix be set to a directory that will hold saord software
    (e.g., --prefix=/soft/saord) in order to make management of our software
    easier.

    NB: be sure to use only absolute path names (those starting with "/")
    in the --prefix and --exec_prefix options. (The configure options we
    use at SAO for various machines are given as examples in the script
    file called "saoconfig" in this directory.)

  2. Type `make' to compile the package.
     This will create a library archive called libxpa.a. It also will create
     the programs xpaget, xpaset, xpainfo, xpaaccess, xpans, and xpamb. It
     also will create the libxpa.so shared object if requested using the
     --enable-shared switch

  3. You can build the libxpa.so shared library manually by executing:

	make shlib

     at this point. This will not contain Xt or Tcl routines. If Tcl support
     has been enabled (see --with-tcl above), you can build a shared library
     called libtclxpa.so that supports the tclxpa package (i.e. Tcl routines
     are contained in it) by executing:

	make tclxpa

     This shared library will be loaded automatically with the Tcl command:

        package require tclxpa 2.1

     assuming, of course, that your shared library can be found by Tcl.

  4. Type "make install" to install XPA's libraries and binaries in
     standard places.  You'll need write permission on the installation
     directories to do this.  The installation directories are
     determined by the "configure" script and may be specified with
     the --prefix and --exec_prefix options to "configure".  See the
     Makefile for information on what directories were chosen; you
     can override these choices by modifying the "prefix" and
     "exec_prefix" variables in the Makefile.

  5. There are .html help files in the doc directory. You can copy
     these files to a more convenient location, if you like. We
     did not automate this step because we did not know where to
     copy these files by default. (NB: The help.html file is the
     top level index file.)

  6. You can remove the program binaries and object files from the
     source code directory by typing `make clean'.  To also remove the
     files that `configure' created (so you can compile the package for
     a different kind of computer), type `make distclean'.  There is
     also a `make maintainer-clean' target, but that is intended mainly
     for the package's developers.  If you use it, you may have to get
     all sorts of other programs in order to regenerate files that came
     with the distribution.

Compilers and Options
=====================

   Some systems require unusual options for compilation or linking that
the `configure' script does not know about.  You can give `configure'
initial values for variables by setting them in the environment:

     ./configure CC=c89 CFLAGS=-O2 LIBS=-lposix 

You also can use this facility to specify a compiler other than the default
gcc (if it exists).

Installation Names
==================

   By default, `make install' will install the package's files in
`/usr/local/bin', `/usr/local/lib', etc.  You can specify an
installation prefix other than `/usr/local' by giving `configure' the
option `--prefix=PATH':

e.g.,
	./configure --prefix=/soft/saord

Programs will be installed in /soft/saord/bin, libraries in /soft/saord/lib,
and include files in /soft/saord/include. We recommend this as a general rule,
in order to keep SAORD software in one place that does not conflict with other
installations. Note that you will need to add the bin directory to your path.

   You can specify separate installation prefixes for architecture-specific
files and architecture-independent files.  If you give `configure' the option
`--exec-prefix=PATH', the package will use PATH as the prefix for installing
programs and libraries. Documentation and other data files will still use the
regular prefix.

   In addition, if you use an unusual directory layout you can give
options like `--bindir=PATH' to specify different values for particular
kinds of files.  Run `configure --help' for a list of the directories
you can set and what kinds of files go in them.

   If the package supports it, you can cause programs to be installed
with an extra prefix or suffix on their names by giving `configure' the
option `--program-prefix=PREFIX' or `--program-suffix=SUFFIX'.

Optional Features
=================

   Some packages pay attention to `--enable-FEATURE' options to
`configure', where FEATURE indicates an optional part of the package.
They may also pay attention to `--with-PACKAGE' options, where PACKAGE
is something like `gnu-as' or `x' (for the X Window System).  The
`README' should mention any `--enable-' and `--with-' options that the
package recognizes.

   For packages that use the X Window System, `configure' can usually
find the X include and library files automatically, but if it doesn't,
you can use the `configure' options `--x-includes=DIR' and
`--x-libraries=DIR' to specify their locations.

Specifying the System Type
==========================

   There may be some features `configure' can not figure out
automatically, but needs to determine by the type of host the package
will run on.  Usually `configure' can figure that out, but if it prints
a message saying it can not guess the host type, give it the
`--host=TYPE' option.  TYPE can either be a short name for the system
type, such as `sun4', or a canonical name with three fields:
     CPU-COMPANY-SYSTEM

See the file `config.sub' for the possible values of each field.  If
`config.sub' isn't included in this package, then this package doesn't
need to know the host type.

   If you are building compiler tools for cross-compiling, you can also
use the `--target=TYPE' option to select the type of system they will
produce code for and the `--build=TYPE' option to select the type of
system on which you are compiling the package.

Sharing Defaults
================

   If you want to set default values for `configure' scripts to share,
you can create a site shell script called `config.site' that gives
default values for variables like `CC', `cache_file', and `prefix'.
`configure' looks for `PREFIX/share/config.site' if it exists, then
`PREFIX/etc/config.site' if it exists.  Or, you can set the
`CONFIG_SITE' environment variable to the location of the site script.
A warning: not all `configure' scripts look for a site script.

Operation Controls
==================

   `configure' recognizes the following options to control how it
operates.

`--cache-file=FILE'
     Use and save the results of the tests in FILE instead of
     `./config.cache'.  Set FILE to `/dev/null' to disable caching, for
     debugging `configure'.

`--help'
     Print a summary of the options to `configure', and exit.

`--quiet'
`--silent'
`-q'
     Do not print messages saying which checks are being made.  To
     suppress all normal output, redirect it to `/dev/null' (any error
     messages will still be shown).

`--srcdir=DIR'
     Look for the package's source code in directory DIR.  Usually
     `configure' can determine that directory automatically.

`--version'
     Print the version of Autoconf used to generate the `configure'
     script, and exit.

`configure' also accepts some other, not widely useful, options.

If you have questions, please contact us at: saord@cfa.harvard.edu.

							Eric Mandel