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                eCos Host-side Software
                =======================

This README file only describes the eCos host-side software. For
details of the eCos target-side software or the required toolchains,
please see other documentation. A good starting point is
http://sourceware.com/ecos
                
There are two categories of host-side software. The host subdirectory
contains generic software, primarily related to the eCos configuration
technology. All eCos users will need to use some of this technology to
configure and build eCos, either using pre-built binaries or by
building the host-side software from source. The generic software
should be portable to a wide range of host platforms.

There is also package-specific host-side software. Much of this is I/O
related. For example the generic USB-slave package contains some
programs related to testing; a test application is run on a target
with suitable USB slave-side hardware, and needs to interact with
another program running on the USB host; the latter is
package-specific host-side software and can be found in the
subdirectory packages/io/usb/slave. Code like this may have
significant platform dependencies and may only work on a single
platform or on a small number of platforms. There may also be
special requirements, for example it may be necessary to install some
programs suid root so that they have appropriate access to the
hardware. 


The host subdirectory includes the following:

infra/
    This is an implementation of the eCos infrastructure that can be
    used on the host-side, and provides assertion, tracing and
    testcase support.

    NOTE: the eCos infrastructure facilities are not especially
    well-suited to host-side development, in particular they are not
    C++-oriented. There are plans to remove the current infrastructure
    completely and replace it with something more suitable. People
    planning new projects should be aware of this, and may wish to
    avoid using the current infrastructure.

libcdl/
    The CDL library lies at the heart of the eCos configuration
    technology. 

tools/configtool/
    The sources to the various configuration tools can be found here.

tools/configtool/common/common/
    Contains sources related to makefile generation, shared by the
    command line and graphical tools.

tools/configtool/standalone/common/
    Contains the command line ecosconfig tool.

tools/configtool/standalone/wxwin/
    Contains sources for the wxWindows-based, Linux and Windows graphical
    configuration tool. The Windows version is built with cygwin g++.
    
tools/configtool/common/win32/
tools/configtool/standalone/win32/
    Contains sources for the older, MFC-based, Windows-only graphical
    configuration tool. This can only be built with Visual C++.

The two graphical configuration tools have their own build procedures,
described in tools/configtool/standalone/wxwin/README.txt and
tools/configtool/standalone/win32/ReadMe respectively.

Package-specific host-side code lives in the host subdirectory of the
appropriate package, for example packages/io/usb/slave/<version>/host.
Most packages only provide target-side code and hence will not have a
host subdirectory. Users can install various packages from a variety
of sources, and where a package does have host-side software the
package documentation should be consulted for further information.


Installing on Linux, Other Unix Systems, and Cygwin
---------------------------------------------------

Both generic host-side software (infra, libcdl and ecosconfig) and
package-specific software can be built with the conventional
"configure/make/make install" sequence. However the code does not
conform fully to GNU coding standards so some operations such as "make
dist" are not supported. There is limited support for DejaGnu-based
testing.

Much of the host-side software has a dependency on Tcl. This is not
supplied with the sources since many users will already have a
suitable installation, for example it is shipped as standard with all
major Linux distributions. The generic host-side software should work
with any release of Tcl from 8.0 onwards. The package-specific
software requires a more recent version, 8.3 or later. If no suitable
Tcl installation is available then the configure step will still
succeed but some of the package-specific software will not be built.

There are two main approaches to building the host-side software:

1) build the generic and the package-specific code in one build tree.
   This uses the top-level configure script. The script automatically
   invokes the configure script in the main host subdirectory. In
   addition it searches the packages hierarchy for host subdirectories
   containing their own configure scripts and will invoke those.

   Note: the search for host subdirectories happens during configure
   time, not during the make. If new packages with host-side code are
   added to the repository then it will be necessary to re-run the
   toplevel configure script.

2) build the generic code in one build tree, using the configure
   script in the toplevel's host subdirectory. Then build some or all
   of the package-specific code in separate build trees, using the
   configure scripts in each package's host subdirectory.

The first approach is generally simpler. However some of the
package-specific code requires special installation, for example a
program may have to be installed suid root so that it has the right
privileges to access hardware, and hence the "make install" step has
to be run by the superuser. Also some of the package-specific code is
rather specialized and may be of no interest to many users. For
example, the USB testing code is only useful when developing
USB-based applications. Hence some users may prefer the second
approach, building just the generic code and a subset of the
package-specific code.

It is necessary to use a separate build tree rather than build
directly in the source tree. This is enforced by the configure scripts.

  $ mkdir build
  $ cd build

The next step is to run the desired configure script. To build all
the host-side software this means the toplevel configure script:

  $ <path>/configure <args>

Alternatively to build just the generic host-side software, use the
configure script in the host subdirectory.

  $ mkdir host
  $ cd host
  $ <path>/host/configure <args>

Or, to build just one package's host-side code:

  $ mkdir -p packages/io/usb/slave/current/host
  $ cd packages/io/usb/slave/current/host
  $ <path>/packages/io/usb/slave/current/host/configure <args>

(It is not actually necessary to use the same directory structure in
the build tree as in the source tree, but doing so can avoid
confusion). 
  
A list of all the command-line options can be obtained by running
"configure --help". The most important ones are as follows:

1) --prefix. This can be used to specify the location of the install
   tree, defaulting to /usr/local, so the ecosconfig program ends up
   in /usr/local/bin/ecosconfig and the CDL library ends up in
   /usr/local/lib/libcdl.a. If an alternative location is preferred
   this can be specified with --prefix, for example:

   $ <path>/configure --prefix=/usr/local/ecos <args>

2) --enable-debug. By default all assertions and tracing are disabled.
   When debugging any of the generic host-side software these should
   be enabled. Some package-specific code may not have any extra
   debug support, in which case --enable-debug would be ignored.

   $ <path>/configure --enable-debug

   It is also possible to control most of the assertion and tracing
   macros at a finer grain. This is intended mainly for use by the
   developers.

   --disable-asserts        disable all assertions
   --disable-preconditions  disable a subset of the assertions
   --disable-postconditions disable a subset of the assertions
   --disable-invariants     disable a subset of the assertions
   --disable-loopinvariants disable a subset of the assertions
   --disable-tracing        disable tracing
   --disable-fntracing      disable function entry/exit tracing

3) --with-tcl=<path>
   --with-tcl-version=<number>
   --with-tk=<path>

   The host-side tools have a dependency on Tcl, which is not supplied
   with the sources because many people will already have a suitable
   installation. Specifically it is necessary to have the header file
   tcl.h and appropriate libraries such that -ltcl will work - this
   can involve either static or shared libraries. Some tools may require
   Tk as well as Tcl.

   Unfortunately there is considerable variation in Tcl installations.
   In theory all Tcl installations have a file tclConfig.sh which
   defines exactly how to compile and link code that uses Tcl, and Tk
   has a similar file tkConfig.sh. The eCos configure scripts look for
   these files, first in $(prefix)/lib, then in /usr/lib. If the system
   already has a Tcl installation in /usr then the configure script will
   automatically find /usr/lib/tclConfig.sh and it is not necessary
   to pass additional options when configuring the eCos host-side
   software. Alternatively, if for example you have installed a more
   recent version of Tcl/Tk in the same place that you want to install the
   eCos software, e.g. /usr/local, then $(prefix)/lib/tclConfig.sh
   will be read in.

   It is also possible that a more recent version of Tcl has been installed
   in a different location. For example, you may wish to install the eCos host
   tools in /opt/ecos but use a version of Tcl installed in /usr/local. The
   eCos configure scripts need to be told explicitly where to look for
   the Tcl:

   $ <path>/configure --with-tcl=/usr/local ...

   Some systems, for example Debian Linux 3.0, do not install tclConfig.sh
   in /usr/lib because that makes it more difficult to have several different
   versions of Tcl installed at the same time. Instead tclConfig.sh is found
   in a versioned directory such as /usr/lib/tcl8.3. Since several versions
   may be installed the desired one must be specified explicitly.

   $ <path>/configure --with-tcl-version=8.3

   The --with-tcl and --with-tcl-version options are combined to give a search path:

      <with-tcl>/lib/tclConfig.sh
      <with-tcl>/lib/tcl<vsn>/tclConfig.sh
      <prefix>/lib/tclConfig.sh
      <prefix>/lib/tcl<vsn>/tclConfig.sh
      /usr/lib/tclConfig.sh
      /usr/lib/tcl<vsn>/tclConfig.sh

   If tclConfig.sh cannot be found in any of these places then it is assumed
   that Tcl has not been properly installed and the eCos configure script will
   fail.

   To search for Tk the configure scripts use much the same rules as
   for Tcl. It is also possible to specify a path using the --with-tk
   option, useful if for some reason Tk has been installed in a
   different location from Tcl. There is no --with-tk-version: it is
   assumed that the same version should be used for both Tcl and Tk.

   Again, the configure scripts must be able to find tkConfig.sh

   Once tclConfig.sh and tkConfig.sh have been found and read in, the eCos
   configure scripts should have all the information needed to compile and
   link code that uses Tcl. First the location of key headers such as
   <tcl.h> is needed. A tclConfig.sh file may define TCL_INCLUDE_SPEC
   or TCL_INC_DIR to give a specific location, otherwise the header
   files should be in $(TCL_PREFIX)/include. If <tcl.h> cannot be
   found then the eCos configure scripts will fail.

   Next it is necessary to work out how to link applications with Tcl. This
   information should be provided by a tclConfig.sh variable TCL_LIB_SPEC.
   Unfortunately not all Tcl installations set this, for example the cygwin
   Tcl 8.4 release. If TCL_LIB_SPEC is not defined then instead the
   configure script will look for a library libtcl<vsn>.a, where <vsn> is
   specified using --with-tcl-version, then for a library libtcl.a.
   tclConfig.sh may also list additional libraries in TCL_LIBS and
   additional linker flags in TCL_LD_FLAGS.

   For Tk the relevant tkConfig.sh settings are TK_INCLUDE_SPEC or
   TK_INC_DIR, TK_XINCLUDES, TK_LIB_SPEC, and TK_LIBS.


Following the configure step the build tree should be set up
correctly. All that remains is the actual build and install:

   $ make
   $ make install

This should result in an ecosconfig executable, plus appropriate
libraries and header files. If the install prefix is a system
location, for example /usr/local/, then "make install" will normally
require root privileges. Also some of the package-specific software
has special installation requirements, for example programs that need
to be installed suid root, and this will also need root privileges.


Installing with Visual C++
--------------------------

Under Windows it is possible to build the generic host-side software
(infra, libcdl and ecosconfig) with Visual C++ but this is deprecated.
Building with g++ under cygwin is preferred.

It is still necessary to run the configure script and a suitable make
utility. That requires a shell and a Unix-like environment, as
provided by cygwin. The Visual C++ compiler cl.exe needs to be on the
shell's search path, and some environment variables such as INCLUDE
and LIB may need to be set to point at the Visual C++ installation -
the details may vary depending on the version of the compiler. Then
the configure command should be run like this:

  $ CC=cl CXX=cl <path>/host/configure <args>

Note that the path should be a cygwin path: cygwin mount points are
accepted and forward slashes should be used. The various configure
scripts now detect that Visual C++ should be used, and adapt
accordingly.

Depending on what cygwin mount points are set up, /usr/local may or
may not be an appropriate install location for VC++ applications.
If not, the install location should be specified with --prefix:

  $ CC=cl CXX=cl <path>/configure --prefix=<install-path> <args>

It is also necessary to use the right version of Tcl. For a VC++ build
the cygwin release of Tcl should not be used. Instead a suitable
prebuilt Tcl package can be obtained from http://www.tcl.tk/.
It is necessary to tell the configure script where this has been
installed, for example:

  $ CC=cl CXX=cl <path>/configure --prefix=<install-path> \
    --with-tcl=/cygdrive/d/local/scriptics/Tcl/tcl8.1 <args>

The library name will be of the form tcl81.lib, and there will not be
a symbolic link from tcl.lib to the appropriate version. It will be
necessary to specify the Tcl version explicitly since the default
version is currently 8.0.

  $ CC=cl CXX=cl <path>/configure --prefix=<install-path> \
    --with-tcl=/d/local/scriptics/Tcl/tcl8.1 --with-tcl-version=81 <args>

Following a successful configure, the tools can be built and installed
in the normal fashion:

  $ make
  $ make install


More Information
================

Please see the eCos web site, http://sourceware.com/ecos/, for
further details. This includes the FAQ, a form for reporting problems,
and details of the various mailing lists
(http://sources.redhat.com/ecos/intouch.html) At the time of writing
there are no separate mailing lists for the eCos host-side sources,
the main mailing list ecos-discuss@sourceware.com should be used
instead.

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