xref: /src/external/bsd/ntp/dist/sntp/libopts/README

        THIS TARBALL IS NOT A FULL DISTRIBUTION.

The contents of this tarball is designed to be incorporated into
software packages that utilize the AutoOpts option automation package
and are intended to be installed on systems that may not have libopts
installed.  It is redistributable under the terms of either the LGPL
(see COPYING.lgpl) or under the terms of the advertising clause free BSD
license (see COPYING.mbsd).

Usage Instructions for autoconf/automake/libtoolized projects:

1. Install the unrolled tarball into your package source tree,
   copying ``libopts.m4'' to your autoconf macro directory.

   In your bootstrap (pre-configure) script, you can do this:

      rm -rf libopts libopts-*
      gunzip -c `autoopts-config libsrc` | tar -xvf -
      mv -f libopts-*.*.* libopts
      cp -fp libopts/m4/*.m4 m4/.

   I tend to put my configure auxiliary files in "m4".
   Whatever directory you choose, if it is not ".", then
   be sure to tell autoconf about it with:

      AC_CONFIG_AUX_DIR(m4)

   This is one macro where you *MUST* remember to *NOT* quote
   the argument.  If you do, automake will get lost.

2. Add an invocation of either LIBOPTS_CHECK or LIBOPTS_CHECK_NOBUILD
   to your configure.ac file.  See LIBOPTS_CHECK: below for details.

3. Add the following to your top level ``Makefile.am'' file:

      if NEED_LIBOPTS
         SUBDIRS += $(LIBOPTS_DIR)
      endif

   where ``<...>'' can be whatever other files or directories you may
   need.  The SUBDIRS must be properly ordered.  *PLEASE NOTE* it is
   crucial that the SUBDIRS be set under the control of an automake
   conditional.  To work correctly, automake has to know the range of
   possible values of SUBDIRS.  It's a magical name with magical
   properties.  ``NEED_LIBOPTS'' will be correctly set by the
   ``LIBOPTS_CHECK'' macro, above.

4. Add ``$(LIBOPTS_CFLAGS)'' to relevant compiler flags and
   ``$(LIBOPTS_LDADD)'' to relevant link options whereever
   you need them in your build tree.

5. Make sure your object files explicitly depend upon the
   generated options header file.  e.g.:

     $(prog_OBJECTS) : prog-opts.h
     prog-opts.h : prog-opts.c
     prog-opts.c : prog-opts.def
         autogen prog-opts.def

6. *OPTIONAL* --
   If you are creating man pages and texi documentation from
   the program options, you will need these rules somewhere, too:

     man_MANS = prog.1
     prog.1 : prog-opts.def
         autogen -Tagman-cmd.tpl -bprog prog-opts.def

     invoke-prog.texi : prog-opts.def
         autogen -Tagtexi-cmd.tpl prog-opts.def

If your package does not utilize the auto* tools, then you
will need to hand craft the rules for building the library.

LIBOPTS_CHECK:

The arguments to both macro are a relative path to the directory with
the libopts source code.  It is optional and defaults to "libopts".
These macros work as follows:

1.  LIBOPTS_CHECK([libopts/rel/path/optional])

    Adds two command-line options to the generated configure script,
    --enable-local-libopts and --disable-libopts-install.  AC_SUBST's
    LIBOPTS_CFLAGS, LIBOPTS_LDADD, and LIBOPTS_DIR for use in
    Makefile.am files.  Adds Automake conditional NEED_LIBOPTS which
    will be true when the local copy of libopts should be built.  Uses
    AC_CONFIG_FILES([$libopts-dir/Makefile]) to cause the local libopts
    into the package build.  If the optional relative path to libopts is
    not provided, it defaults to simply "libopts".

2.  LIBOPTS_CHECK_NOBUILD([libopts/rel/path/optional])

    This variant of LIBOPTS_CHECK is useful when multiple configure.ac
    files in a package make use of a single libopts tearoff.  In that
    case, only one of the configure.ac files should build libopts and
    others should simply use it.  Consider this package arrangment:

    all-tools/
      configure.ac
      common-tools/
        configure.ac
        libopts/

    The parent package all-tools contains a subpackage common-tools
    which can be torn off and used independently.  Programs configured
    by both configure.ac files link against the common-tools/libopts
    tearoff, when not using the system's libopts.  The top-level
    configure.ac uses LIBOPTS_CHECK_NOBUILD([common-tools/libopts]),
    while common-tools/configure.ac uses LIBOPTS_CHECK.  The difference
    is LIBOPTS_CHECK_NOBUILD will never build the libopts tearoff,
    leaving that to the subpackage configure.ac's LIBOPTS_CHECK.
    Specifically, LIBOPTS_CHECK_NOBUILD always results in the
    NEED_LIBOPTS Automake conditional being false, and does not invoke
    AC_CONFIG_FILES(path-to-libopts/Makefile).

LICENSING:

This material is Copyright (C) 1992-2018 by Bruce Korb.  You are
licensed to use this under the terms of either the GNU Lesser General
Public License (see: COPYING.lgpl), or, at your option, the modified
Berkeley Software Distribution License (see: COPYING.mbsd).  Both of
these files should be included with this tarball.