[/
 / Copyright (c) 2003 Boost.Test contributors 
 /
 / Distributed under the Boost Software License, Version 1.0. (See accompanying
 / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 /]

[section:usage_variants Usage variants]

The __UTF__ supports three different usage variants:

# [link boost_test.usage_variants.single_header The single-header variant]
# [link boost_test.usage_variants.static_lib    The static library variant]
# [link boost_test.usage_variants.shared_lib    The shared library variant]

In most cases you shouldn't have problems deciding which one to use, since there are
clear reasons why would you prefer each one. Following sections should help you with the decision.

[/ ##################################################################### ]
[h3:single_header Single-header usage variant]

If you prefer to avoid the compilation of standalone library, you should use the 
single-header variant of the __UTF__. This variant only requires you to include, 
as it follows from its name, the single header: `#include <boost/test/included/unit_test.hpp>`
and there is no need to link with any library. There are several ways to perform 
the initialization, but the simplest way is this:
``
  #define __BOOST_TEST_MODULE__ test module name
  #include <boost/test/included/unit_test.hpp>
``
__BOOST_TEST_MODULE__ macro needs to be defined *before* the include and should be set to 
test module name. This name can include spaces and does not need to be wrapped in quotes. 

The limitation of single header variant is that you can only implement this way 
test modules with a single translation unit. 

For more details on customization for this usage variant you can check [link 
boost_test.adv_scenarios.single_header_customizations this section].

[/ ##################################################################### ]
[h3:static_lib Static library usage variant]
For most users, who has an access to pre-built static library [footnote these files are distributed 
with the packaging systems on Linux and OSX for instance] of the __UTF__ or can 
[link boost_test.adv_scenarios.build_utf build it] themselves, following usage can be most versatile
 and simple approach. This usage variant entails two steps. 

# First you need to add following line to all translation units in a test module:
  ``
    #include <boost/test/unit_test.hpp>
  ``
  and *only one* translation unit should include following lines
  ``
    #define __BOOST_TEST_MODULE__ test module name
    #include <boost/test/unit_test.hpp>
  ``
  __BOOST_TEST_MODULE__ macro needs to be defined *before* the include and should be set to 
  test module name. This name can include spaces and does not need to be wrapped in quotes. 
# The second step is to link with the __UTF__ static library.

[note Header `<boost/test/unit_test.hpp>` is an 'aggregate' header: it includes most of the other headers that contains the Unit Test Framework definitions.]

The flip side of this usage variant is that each test module following this usage variant is going 
to be statically linked with __UTF__, which might be something you interested to avoid (to save space 
for example). For more information about these configuration options check 
[link boost_test.adv_scenarios.static_lib_customizations this section].

[/ ##################################################################### ]
[h3:shared_lib Shared library usage variant]
In the project with large number of test modules the static library variant of the __UTF__ may
cause you to waste a lot of disk space. The solution is to link test module dynamically with the 
__UTF__ built as a shared library. 
This usage variant entails two steps. 

# First you need to add following lines to all translation units in a test module:
  ``
    #define __BOOST_TEST_DYN_LINK__
    #include <boost/test/unit_test.hpp>
  ``
  and *only one* translation unit should include following lines
  ``
    #define __BOOST_TEST_MODULE__ test module name
    #define __BOOST_TEST_DYN_LINK__
    #include <boost/test/unit_test.hpp>
  ``
  `BOOST_TEST_MODULE` and `BOOST_TEST_DYN_LINK` macros needs to be defined *before* the include. 
  `BOOST_TEST_MODULE` should be set to test module name. This name can include spaces and does 
  not need to be wrapped in quotes. 

# The second step is to link with the __UTF__ shared library.

The flip side of this usage variant is that you will need to make sure the __UTF__ shared library
is accessible at runtime to a test module.

In addition shared library usage variant facilitates custom test runners. For more information about this 
check [link boost_test.adv_scenarios.shared_lib_customizations this section].

[caution On Windows, the test module and the __UTF__ shared library should link to the same CRT. Not doing
 so (for instance __UTF__ shared library in /release/ mode while the test module is in /debug/) will
 lead to crashes.]

[endsect] [/Usage Variants]

[/ EOF]
