groff/dist/README.MinGW

README.MinGW
============

Contributed by Keith Marshall (keith.d.marshall (a] ntlworld.com)


INTRODUCTION
------------

This file provides recommendations for building a Win32 implementation of
GNU Groff, using the MinGW port of GCC for Microsoft (TM) Windows-32
platforms.  It is intended to supplement the standard installation
instructions (see file INSTALL); it does not replace them.

You require both the MinGW implementation of GCC and its supporting MSYS
toolkit, which provides a Win-32 implementation of the GNU bash shell, and a
few other essential utilities; these may be obtained from

  http://sourceforge.net/projects/mingw

by following the appropriate download links, where they are available as
self-extracting executable installation packages.  If installing both from
scratch, it is recommended that MinGW is installed first, as the MSYS
installer can then automatically set up the proper environment for running
MinGW.

Additionally, if you wish to compile groff with support for its HTML output
capability, some additional tools are required as decribed in the section
PREREQUISITES FOR HTML OUTPUT later in this file.


BUILDING GROFF WITH MINGW
-------------------------

Assuming that you have obtained the appropriate groff distribution, and that
you are already running an MSYS shell, then the configuration, compilation,
and installation of groff, using MinGW, is performed in much the same way as
it is described in the INSTALL file, which is provided with the groff
distribution.  The installation steps are summarised below:

1. Change working directory to any suitable location where you may unpack
   the groff distribution; you must be authorized for write access.
   Approximately 30MB of free disk space are needed.

2. Unpack the groff distribution:

     tar xzf <download-path>/groff-<version>.tar.gz

   This creates a new sub-directory, groff-<version>, containing an image of
   the groff source tree.  You should now change directory, to make this
   ./groff-<version> your working directory.

3. If you are intending to build groff with support for HTML output, then
   you must now ensure that the prerequisites described in the later section
   PREREQUISITES FOR HTML OUTPUT are satisfied, before proceeding to build
   groff; in particular, please ensure that all required support programs
   are installed in the current PATH.

4. You are now ready to configure, build, and install groff.  This is
   accomplished using the conventional procedure, as described in the file
   INSTALL, i.e.

     ./configure --prefix=<win32-install-path> ...
     make
     make install

   Please observe the syntax for the configure command, indicated above; the
   default value for --prefix is not suitable for use with MinGW, so the
   --prefix=<win32-install-path> option must be specified, where
   <win32-install-path> is the chosen MS-Windows directory in which the
   groff application files are to be installed (see the later section
   entitled CHOOSING AN INSTALLATION PATH).  Any other desired configuration
   options may also be specified, as described in the standard groff
   installation instructions.

5. After completing the above, groff should be successfully installed; the
   build directory is no longer required; it may be simply deleted in its
   entirety.  Alternatively, you may choose to keep it, but to remove all
   files which can be reproduced later, by repeating the configure, make and
   make install steps; this is readily accomplished by the command

     make distclean


This completes the installation of groff; please read the final sections of
this file, GROFF RUNTIME ENVIRONMENT and CAVEATS AND BUGS, for advice on
setting up the runtime environment, and avoiding known runtime problems,
before running groff.


CHOOSING AN INSTALLATION PATH
-----------------------------

It may be noted that the above instructions indicate that the ./configure
command must be invoked with an argument specifying a preference for
--prefix=<win32-install-path>, whereas the standard groff installation
instructions indicate that this may be omitted, in which case it defaults to
--prefix=/usr/local.

In the case of building with MinGW, the default behaviour of configure is
not appropriate for the following reasons.

o The MSYS environment creates a virtual UNIX-like file system, with its
  root mapped to the actual MS-Windows directory where MSYS itself is
  installed; /usr is also mapped to this MSYS installation directory.

o All of the MSYS tools, and the MinGW implementation of GCC, refer to files
  via this virtual file system representation; thus, if the
  --prefix=<win32-install-path> is not specified when groff is configured,
  `make install' causes groff to be installed in <MSYS-install-path>/local.

o groff needs to know its own installation path, so that it can locate its
  own installed components.  This information is compiled in, using the
  exact form specified with the --prefix=<win32-install-path> option to
  configure.

o Knowledge of the MSYS virtual file system is not imparted to groff; it
  expects the compiled-in path to its components to be a fully qualified
  MS-Windows path name (although UNIX-style slashes are permitted, and
  preferred to the MS-Windows style backslashes, to demarcate the directory
  hierarchy).  Thus, when configuring groff, if
  --prefix=<win32-install-path> is not correctly specified, then the
  installed groff application looks for its components in /usr/local, and
  most likely doesn't find them, because they are actually installed in
  <MSYS-install-path>/local.

It is actually convenient, but by no means a requirement, to have groff
installed in the /usr/local directory of the MSYS virtual file system; this
makes it easy to invoke groff from the MSYS shell, since the virtual
/usr/local/bin is normally added automatically to the PATH (the default
PATH, as set in MSYS's /etc/profile), when MSYS is started.

In order to install groff into MSYS's /usr/local directory, it is necessary
to specify the fully qualified absolute MS-Windows path to this directory,
when configuring groff, i.e.

  ./configure --prefix=<MSYS-install-path>/local ...

For example, on a system where MSYS is installed in the MS-Windows directory
D:\MSYS\1.0, the MSYS virtual path /usr/local resolves to the absolute
MS-Windows native path D:\MSYS\1.0\local (the /usr component of the MSYS
virtual path does not appear in the resolved absolute native path name since
MSYS maps this directly to the root of the MSYS virtual file system).  Thus,
the --prefix option should be specified to configure as

  ./configure --prefix=D:/MSYS/1.0/local ...

Note that the backslash characters, which appear in the native MS-Windows
form of the path name, are replaced by UNIX-style slashes in the argument to
configure; this is the preferred syntax.

Also note that the MS-Windows device designator (D: in this instance) is
prepended to the specified path, in the normal MS-Windows format, and that,
since upper and lower case distinctions are ignored in MS-Windows path
names, any combination of upper and lower case is acceptable.


PREREQUISITES FOR HTML OUTPUT
-----------------------------

If you intend to use groff for production of HTML output, then there are a
few dependencies which must be satisfied.  Ideally, these should be resolved
before attempting to configure and build groff, since the configuration
script does check them.

In order to produce HTML output, you first require a working implementation
of Ghostscript; either the AFPL Ghostscript or the GNU Ghostscript
implementation for MS-Windows should be suitable, depending on your
licensing preference.  It is highly recommended to use version 8.11 or
higher due to bugs in older versions.  These may be obtained, in the form of
self-installing binary packages, by following the download links for the
chosen licensing option, from http://sourceforge.net/projects/ghostscript.

Please note that these packages install the Ghostscript interpreter required
by groff in the ./bin subdirectory of the Ghostscript installation
directory, with the name gswin32c.exe.  However, groff expects this
interpreter to be located in the system PATH, with the name gs.exe.  Thus,
to ensure that groff can correctly locate the Ghostscript interpreter, it is
recommended that the file gswin32c.exe should be copied from the Ghostscript
installation directory to the MSYS /usr/local/bin directory, where it should
be renamed to gs.exe.

In addition to a working Ghostscript interpreter, you also require several
image manipulation utilities, all of which may be scavenged from various
packages available from http://sourceforge.net/projects/gnuwin32, and which
should be installed in the MSYS /usr/local/bin directory, or any other
suitable directory which is specified in the PATH.  These additional
prerequisites are

  1. from the netpbm-<version>-bin.zip package:

       netpbm.dll
       pnmcrop.exe
       pnmcut.exe
       pnmtopng.exe
       pnmtops.exe

  2. from the libpng-<version>-bin.zip package:

       libpng.dll

  3. from the zlib-<version>-bin.zip package:

       zlib-1.dll, which must be renamed to zlib.dll

  4. from the psutils-<version>-bin.zip package:

       psselect.exe

Note that it is not necessary to install the above four packages in their
entirety; of course, you may do so if you wish.


GROFF RUNTIME ENVIRONMENT
-------------------------

The runtime environment, provided to groff by MSYS, is essentially the same
as would be provided under a UNIX or GNU/Linux operating system; thus, any
environment variables which may be used to customize the groff runtime
environment have similar effects under MSYS, as they would in UNIX or
GNU/Linux, with the exception that any variable specifying a path should
adopt the same syntax as a native MS-Windows PATH specification.

There is, however, one known problem which is associated with the
implementation of the MS-Windows file system, and the manner in which the
Microsoft runtime library (which is used by the MinGW implementation of GCC)
generates names for temporary files.  This known problem arises when groff
is invoked with a current working directory which refers to a network share,
for which the user does not have write access in the root directory, and
there is no environment variable set to define a writeable location for
creating temporary files.  When these conditions arise, groff fails with a
`permission denied' error, as soon as it tries to create any temporary file.

To specify the location for creating temporary files, the standard UNIX or
GNU/Linux implementation of groff provides the GROFF_TMPDIR or TMPDIR
environment variables, whereas MS-Windows applications generally use TMP or
TEMP; furthermore, the MS-Windows implementations of Ghostscript apparently
support the use of only TEMP or TMPDIR.

To avoid problems with creation of temporary files, it is recommended that
you ensure that both TMP and TEMP are defined, with identical values, to
point to a suitable location for creating temporary files; many MS-Windows
boxes have them set already, and groff has been adapted to honour them, when
built in accordance with the preceding instructions, using MinGW.


CAVEATS AND BUGS
----------------

There are two known issues, observed when running groff in the MinGW/MSYS
environment, which would not affect groff in its native UNIX environment:

o Running groff with the working directory set to a subdirectory of a
  network share, where the user does not have write permission in the root
  directory of the share, causes groff to fail with a `permission denied'
  exception, if the TMP environment variable is not appropriately defined;
  it may also be necessary to define the TEMP environment variable, to avoid
  a similar failure mode, when using the -Thtml output mode of groff.  This
  problem is more fully discussed in the preceding section, GROFF RUNTIME
  ENVIRONMENT.

o When running groff (or nroff) to process standard input, where the
  standard input stream is obtained directly from the RXVT console provided
  with MSYS, groff cannot detect the end-of-file condition for the standard
  input stream, and hangs.  This appears to be caused by a fault in the MSYS
  implementation of RXVT; it may be worked around by either starting MSYS
  without RXVT (see the comments in the MSYS.BAT startup script); in this
  case standard input is terminated by typing <Ctrl-Z> followed by <RETURN>,
  on a new input line.  Alternatively, if you prefer to use MSYS with RXVT,
  you can enter the interactive groff command in the form

    cat | groff ...

  in which case <Ctrl-D> terminates the standard input stream, in just the
  same way it does on a UNIX system; the cat executable provided with MSYS
  does seem to trap the end-of-file condition, and properly signals groff
  that the input stream has terminated.