-------------------------------------------------------------------------------

                             PREREQUSITES

This package is built using CMake.

CMake is an open-source, cross-platform family of tools designed to build,
test and package software. CMake is used to control the software compilation
process using simple platform and compiler independent configuration files,
and generate native makefiles and workspaces that can be used in the compiler
environment of your choice.

If you are already familiar with GNU autoconf tools, CMake basically replaces
the "autogen.sh" and "configure" steps with a portable, platform independent
way of creating makefiles that can be used to build your project/package with.

CMake can be downloaded and installed from:


    https://cmake.org/


-------------------------------------------------------------------------------

                                CLANG

To build on Linux platforms using clang instead of gcc, simply export the
CC and CXX flags before invoking CMake:


    $ export CC=clang
    $ export CXX=clang++
    $ cmake srcdir


If clang/clang++ is not in your $PATH, then you will need to specify its
full path in the CC/CXX export commands.

-------------------------------------------------------------------------------

                          BUILDING DECNUMBER

                      (manual Command Line method)


The decNumber project is hosted on GitHub at the following URL:


    https://github.com/sdl-hercules-390/decNumber


You can either clone the git repository (recommended) or download the source
code .zip file from github.  (click the green "Clone or download" button and
select "Download")

Once downloaded, create a build directory (*outside* the source/repostiory
directory) where the build will take place, called:


    xxxxxxxxAA.yyyyyyy


where "xxxxxxxx" is the name of the project/package (e.g. "decNumber"), "AA"
is the build architecture ("32" or "64") and "yyyyyyy" is the configuration
type ("Debug" or "Release"):


    mkdir  decNumber32.Debug
    mkdir  decNumber32.Release
    mkdir  decNumber64.Debug
    mkdir  decNumber64.Release


On Windows, "xxxxxxxxAA" will be used for the INSTALL_PREFIX (the name of
the directory where the package will be installed to (target of make install).
On Linux, the default INSTALL_PREFIX is /usr/local.  Either can be overridden
by specifying the "-D INSTALL_PREFIX=instdir" option on your cmake command.

Once the binary/build directory is created, to build and install the package
into the specified installation directory, simply use the commands:


  (Windows)

    > mkdir <build-dir>
    > cd <build-dir>
    > srcdir\vstools [32|64]
    > cmake -G "NMake Makefiles" srcdir
    > nmake
    > nmake install


  (Linux)

    $ mkdir <build-dir>
    $ cd <build-dir>
    $ cmake srcdir
    $ make
    # (sudo) make install


Where "srcdir" is the package's source (repository) directory where the
"CMakeLists.txt" file exists.

The "vstools.cmd" batch file (Windows only) initializes the proper Microsoft
Visual C/C++ build environment for the chosen build architecture (32 bit or
64 bit) and must be issued before the cmake and nmake commands.

To override the default installation directory use the -D INSTALL_PREFIX=xxx
cmake option:


  (Windows)

    > cmake -G "NMake Makefiles"  -D INSTALL_PREFIX=dirpath  srcdir


  (Linux)

    $ cmake  -D INSTALL_PREFIX=dirpath  srcdir


Surround "INSTALL_PREFIX=dirpath" with double quotes if it contains blanks.

-------------------------------------------------------------------------------

                           BUILDING DECNUMBER

                     (automated Command Line method)


To make things REALLY SIMPLE on both Windows and Linux you can instead use
the provided "build" script ('build.cmd' on Windows, just 'build' on Linux)
which performs the complete build for you by automatically creating all of
the needed build directories and then invoking all needed commands in turn
to build and install the package for the given architecture/configuration.

To use the automated build method all you need to do is first create a WORK
directory *outside* of (but at the same level as) the package's source code
(i.e. repository) directory, with the name of the package (e.g. decNumber).

Then, from within that WORK directory, simply invoke the package's "build"
script:


  ..\decNumber-repo\build --pkgname . --all --install ..\hercpkgs


This will build the package (within your WORK directory) and automatically
install the results into the specified common external packages directory
(e.g. 'hercpkgs').

Then, for Windows, add that directory's 'lib' subdirectory to your system's
'LIB' environment variable before you build Hercules. (Remember, this only
needs to be done once and never again!).

For Linux, just specify that same directory for your "--enable-extpkgs=DIR"
configure option during your Hercules build:


  ./configure  ...  --enable-extpkgs=../hercpkgs


Enter "build --help" and/or refer to the appropriate Hercules documentation
for more information regarding building Hercules external packages.

-------------------------------------------------------------------------------

                           BUILDING DECNUMBER

                       (Visual Studio GUI method)


To make things EVEN SIMPLER on Windows (but with one minor snag), simply
open the provided Visual Studio solution (.sln) file and then click the
"Rebuild All" toolbar button.

Visual Studio will automatically invoke the appropriate "build.cmd" for
you for whichever platform and configuration that you've selected in its
Build toolbar's list boxes.

Like the previous manual Command Line method, this method presumes you've
created an appropriately named WORK directory at the same level with the
same name as the Project ("decNumber" in this case).

The only "snag" (gotcha) is the package gets installed into a subdirectory
within the WORK directory and not directly into your desired Hercules
directory.  As a result, once you've built all of your architecture and
configuration combinations, you will have to manually copy the results to
your Hercules's package subdirectory.  This is because Visual Studio does
not know ahead of time what Hercules directory you want to install into
(so it instead it does the install to your WORK directory).

If you are experienced with Visual Studio however, you can manually edit
the "Build Command Line", "Rebuild All Command Line" and "Clean Command
Line" project properties with your desired --install directory so that
a Solution Build will then automatically install the package into your
desired Hercules subdirectory, eliminating the need for the manual copy.

-------------------------------------------------------------------------------

                          NON-X86 ARCHITECTURES

To build a non-x86 architectural version of an external package simply build
it like normal (as explained in the automated Command Line method above) but
add a "--cpu xxx" option to your build command to cause the lib files to be
installed into their own unique subdirectory within the specified directory:


  ../decNumber-repo/build --pkgname . --all --cpu xxx --install ../hercpkgs


Hercules currently understands the following non-x86 cpu architectures: arm,
mips, ppc, sparc, xscale, s390x and unknown.

-------------------------------------------------------------------------------
