,-------------------------------------------------.
  |   ____                  _               _  _    |
  |  | __ )  ___   ___  ___| |_   _ __ ___ | || |   |
  |  |  _ \ / _ \ / _ \/ __| __| | '_ ` _ \| || |_  |
  |  | |_) | (_) | (_) \__ \ |_ _| | | | | |__   _| |
  |  |____/ \___/ \___/|___/\__(_)_| |_| |_|  |_|   |
  |                                                 |
  `-------------------------------------------------'

This package provides a set of M4 macros to use with GNU Autoconf.  The
purpose of these macros is to be able to easily find and test the various
Boost libraries of a given version for a given compiler.  This package is
released under GPLv3+.
This macro requires that you use GNU Libtool and assumes that you already
use GNU Automake.  If you don't already use Libtool, the step 3 below
explains how to set it up.

HOWTO
-----

1. If you have an invocation of AC_CONFIG_AUX_DIR in your configure.ac, then
   copy build-aux/boost.m4 in the directory specified by AC_CONFIG_AUX_DIR.
   Otherwise, copy the file at the root of your project.
2. In your top-level Makefile.am (this supposes that you use automake, which
   you most likely do) add:
     ACLOCAL_AMFLAGS = -I <dir>
   where `<dir>' is the (relative) path to the directory where you copied
   boost.m4 (set it to `.' if you put boost.m4 in the same, top-level
   directory).
3. If you don't use GNU Libtool already, then time has come to do the switch.
   Add AC_PROG_LIBTOOL to your configure.ac then, in all the Makefile.am of
   your project, change *_LIBRARIES to *_LTLIBRARIES (notice the extra `LT')
   for each of your library that depends on Boost.  This way, Automake will
   delegate the build of your libraries to Libtool which will do the necessary
   magic so that you won't have to deal with LD_LIBRARY_PATH issues and so on.
   For programs however, you don't have anything special to do, Libtool will
   take care of them.
4. Then, add a call to BOOST_REQUIRE to your configure.ac as well as other
   calls to the various BOOST_* macros that check for the libraries you need.
5. Adjust your Makefile.am where you build targets that depend on Boost so
   that they use $(BOOST_CPPFLAGS), $(BOOST_*_LDFLAGS) and $(BOOST_*_LIBS)
   where appropriate (where `*' is the capitalized name of one of the
   libraries you checked for, e.g.: $(BOOST_THREADS_LDFLAGS)). E.g.:
      bin_PROGRAMS = foo
      foo_SOURCES = foo.cc
      foo_CPPFLAGS = $(BOOST_CPPFLAGS)
      foo_LDFLAGS = $(BOOST_THREAD_LDFLAGS)
      foo_LIBS = $(BOOST_THREAD_LIBS)
   Or if you have more than one target in the same Makefile.am and your
   targets don't have per-target specific flags (such as foo_LIBS) and you
   want all your targets to use the same set of Boost libraries, you can do
   the following instead:
      bin_PROGRAMS = foo bar
      foo_SOURCES = foo.cc
      bar_SOURCES = bar.cc
      AM_CPPFLAGS = $(BOOST_CPPFLAGS)
      AM_LDFLAGS = $(BOOST_THREADS_LDFLAGS)
      LIBS = $(BOOST_THREAD_LIBS)
   Remember that for targets that are programs, you must use LDADD or
   progname_LDADD, but for libraries you must use LIBS or libname_LIBS.

MACROS
------
This section documents the various macros provided by boost.m4.

  BOOST_REQUIRE([VERSION])
  ~~~~~~~~~~~~~~~~~~~~~~~~
The first, most important macro, is BOOST_REQUIRE.  You should invoke it
before other BOOST_* macros if you want to check that Boost has a minimum
given version.

Here are some examples:
  # Do not require any specific minimum version
  BOOST_REQUIRE
  # Require at least 1.34.1
  BOOST_REQUIRE([1.34.1])
  # Require a version number known at runtime
  BOOST_REQUIRE([$some_shell_variable])

This macro defines the Make symbol BOOST_CPPFLAGS.


There are various predefined macros to check for common Boost libraries.
They are ordered in two categories: the Boost libraries that are only made of
headers, and the Boost libraries that (may) require linking to an installed
library.

  Header-only Boost libraries
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~
For each of the Boost libraries that are only made of headers, the macro to
invoke is BOOST_<LIB-NAME> where <LIB-NAME> is the capitalized name of the
library.  Here is the list of libraries for which checks have been
implemented:
    - Array
    - Asio
    - Bind
    - Conversion
    - Foreach
    - Format
    - Function
    - Hash (aka Functional/Hash)
    - Lambda
    - Math
    - MultiArray
    - NumericConversion
    - Preprocessor
    - Utility
    - Ref
    - SmartPtr
    - StringAlgo
    - Tokenizer
    - Tribool
    - Tuple
    - Variant
    - Xpressive
Thus you can invoke BOOST_FOREACH (for instance).  It will check that
<boost/foreach.hpp> works and define the preprocessor symbol
HAVE_BOOST_FOREACH_HPP.  For each of the libraries mentioned above, a couple
of headers are checked (the most important ones) and preprocessor symbols are
defined in an identical fashion.
If the check fails, configure with abort with a fatal error.

  Boost libraries requiring linking
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
For the other Boost libraries that (may) requiring linking to an installed
library (shared or not), the macro to invoke is BOOST_<LIB-NAME> (surprise!)
but this time the macro can take an optional argument to specify the runtime
options you'd like to have.  Most of the time, Boost libraries are compiled
in several flavors, such as with or without debug, with a multi-thread
runtime or not, etc.  The macro will try to find a library that matches your
requirements but may fall back to another flavor of the library if the one you
asked for isn't available.
The following libraries are supported:
  - Chrono
  - Date_Time
  - Filesystem
  - Graph
  - IOStreams
  - Program_options
  - Regex
  - Serialization
  - Signals
  - System
  - Test (aka Unit Test Framework)
  - Threads
  - Wave
Thus you can invoke BOOST_GRAPH (for instance) or BOOST_THREADS([mt-d]).
The optional argument is made of one or more of the following letters:
  sgdpn (in that order)
where:
  s = static runtime
  d = debug build
  g = debug/diagnostic runtime
  p = STLPort build
  n = (unsure) STLPort build without iostreams from STLPort
      (it looks like `n' must always be used along with `p').
Additionally, it can start with `mt-' to indicate that there is a preference
for multi-thread builds.

If the check is successful, at least one header has been checked and the
corresponding preprocessor symbol HAVE_BOOST_*_HPP is defined, along with the
compilation flags BOOST_<LIB-NAME>_LDFLAGS and BOOST_<LIB-NAME>_LIBS.

Small pitfall: BOOST_TEST generates BOOST_UNIT_TEST_FRAMEWORK_LDFLAGS and
BOOST_UNIT_TEST_FRAMEWORK_LIBS, not BOOST_TEST_LFDLAGS and BOOST_TEST_LIBS.
Sorry for the inconsistency.

NOTE: If you intend to use Wave/Spirit with thread support, make sure you
call BOOST_THREADS first.

  Writing your own checks / supporting more Boost libraries
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
All the pre-existing library checks are written with help of
BOOST_FIND_HEADER and BOOST_FIND_LIB.  These two macros are very easy to use
and are documented in boost.m4.  Reading their documentation and reading the
existing library checks should help you to easily write your own additional
checks.  Please contribute them to me by email to <tsuna at lrde.epita.fr>.

You can checkout the Git source tree of this package at
http://github.com/tsuna/boost.m4
Or simply download the latest version:
   wget http://github.com/tsuna/boost.m4/raw/master/build-aux/boost.m4
Patches welcome.

LICENSE
-------

The code of boost.m4 is released under GPLv3+ with the following additional
clause:

 Additional permission under section 7 of the GNU General Public
 License, version 3 ("GPLv3"):

 If you convey this file as part of a work that contains a
 configuration script generated by Autoconf, you may do so under
 terms of your choice.

This clause has been written by FSF lawyers for Autotools.  If you have any
concerns about legal issues, do not contact me as I Am Not A Lawyer.  I
*think* you can get advices at <copyright-clerk at fsf dot org>.  The intent
here is to keep the code Free but to allow anyone to *use* it.