How to use the b2.build.feature.feature function in b2

feature.feature ('link', ['shared', 'static'], ['propagated'])
    feature.feature ('runtime-link', ['shared', 'static'], ['propagated'])
    feature.feature ('runtime-debugging', ['on', 'off'], ['propagated'])


    feature.feature ('optimization',  ['off', 'speed', 'space'], ['propagated'])
    feature.feature ('profiling', ['off', 'on'], ['propagated'])
    feature.feature ('inlining', ['off', 'on', 'full'], ['propagated'])

    feature.feature ('threading', ['single', 'multi'], ['propagated'])
    feature.feature ('rtti', ['on', 'off'], ['propagated'])
    feature.feature ('exception-handling', ['on', 'off'], ['propagated'])

    # Whether there is support for asynchronous EH (e.g. catching SEGVs).
    feature.feature ('asynch-exceptions', ['off', 'on'], ['propagated'])

    # Whether all extern "C" functions are considered nothrow by default.
    feature.feature ('extern-c-nothrow', ['off', 'on'], ['propagated'])

    feature.feature ('debug-symbols', ['on', 'off'], ['propagated'])
    feature.feature ('define', [], ['free'])
    feature.feature ('undef', [], ['free'])
    feature.feature ('include', [], ['free', 'path']) #order-sensitive
    feature.feature ('cflags', [], ['free'])
    feature.feature ('cxxflags', [], ['free'])
    feature.feature ('asmflags', [], ['free'])
    feature.feature ('linkflags', [], ['free'])
    feature.feature ('archiveflags', [], ['free'])
    feature.feature ('version', [], ['free'])

    feature.feature ('location-prefix', [], ['free'])

# the OS under which bjam is running. Even though this should really be a fixed
    # property we need to list all the values to prevent unknown value errors. Both
    # set the default value to the current OS to account for the default use case of
    # building on the target OS.
    feature.feature('host-os', __os_names)
    feature.set_default('host-os', default_host_os())

    feature.feature('target-os', __os_names, ['propagated', 'link-incompatible'])
    feature.set_default('target-os', default_host_os())
    
    feature.feature ('toolset', [], ['implicit', 'propagated' ,'symmetric'])
    
    feature.feature ('stdlib', ['native'], ['propagated', 'composite'])
    
    feature.feature ('link', ['shared', 'static'], ['propagated'])
    feature.feature ('runtime-link', ['shared', 'static'], ['propagated'])
    feature.feature ('runtime-debugging', ['on', 'off'], ['propagated'])
    
    
    feature.feature ('optimization',  ['off', 'speed', 'space'], ['propagated'])
    feature.feature ('profiling', ['off', 'on'], ['propagated'])
    feature.feature ('inlining', ['off', 'on', 'full'], ['propagated'])
    
    feature.feature ('threading', ['single', 'multi'], ['propagated'])
    feature.feature ('rtti', ['on', 'off'], ['propagated'])
    feature.feature ('exception-handling', ['on', 'off'], ['propagated'])

    # Whether there is support for asynchronous EH (e.g. catching SEGVs).
    feature.feature ('asynch-exceptions', ['on', 'off'], ['propagated'])

    # Whether all extern "C" functions are considered nothrow by default.
    feature.feature ('extern-c-nothrow', ['off', 'on'], ['propagated'])

'on'],        # Enable coverage generation for the tool.
        ['incidental', 'propagated'])

    feature.feature('c++-template-depth',
        [str(i) for i in range(64,1024+1,64)] +
        [str(i) for i in range(20,1000+1,10)] +
        #   Maximum template instantiation depth guaranteed for ANSI/ISO C++
        # conforming programs.
        ['17'],
        ['incidental', 'optional', 'propagated'])

    feature.feature ('source', [], ['free', 'dependency', 'incidental'])
    feature.feature ('library', [], ['free', 'dependency', 'incidental'])
    feature.feature ('file', [], ['free', 'dependency', 'incidental'])
    feature.feature ('find-shared-library', [], ['free']) #order-sensitive ;
    feature.feature ('find-static-library', [], ['free']) #order-sensitive ;
    feature.feature ('library-path', [], ['free', 'path']) #order-sensitive ;
    # Internal feature.
    feature.feature ('library-file', [], ['free', 'dependency'])

    feature.feature ('name', [], ['free'])
    feature.feature ('tag', [], ['free'])
    feature.feature ('search', [], ['free', 'path']) #order-sensitive ;
    feature.feature ('location', [], ['free', 'path'])

    feature.feature ('dll-path', [], ['free', 'path'])
    feature.feature ('hardcode-dll-paths', ['true', 'false'], ['incidental'])


    # This is internal feature which holds the paths of all dependency
    # dynamic libraries. On Windows, it's needed so that we can all
    # those paths to PATH, when running applications.

feature.feature ('source', [], ['free', 'dependency', 'incidental'])
    feature.feature ('library', [], ['free', 'dependency', 'incidental'])
    feature.feature ('file', [], ['free', 'dependency', 'incidental'])
    feature.feature ('find-shared-library', [], ['free']) #order-sensitive ;
    feature.feature ('find-static-library', [], ['free']) #order-sensitive ;
    feature.feature ('library-path', [], ['free', 'path']) #order-sensitive ;
    # Internal feature.
    feature.feature ('library-file', [], ['free', 'dependency'])

    feature.feature ('name', [], ['free'])
    feature.feature ('tag', [], ['free'])
    feature.feature ('search', [], ['free', 'path']) #order-sensitive ;
    feature.feature ('location', [], ['free', 'path'])

    feature.feature ('dll-path', [], ['free', 'path'])
    feature.feature ('hardcode-dll-paths', ['true', 'false'], ['incidental'])


    # This is internal feature which holds the paths of all dependency
    # dynamic libraries. On Windows, it's needed so that we can all
    # those paths to PATH, when running applications.
    # On Linux, it's needed to add proper -rpath-link command line options.
    feature.feature ('xdll-path', [], ['free', 'path'])

    #provides means to specify def-file for windows dlls.
    feature.feature ('def-file', [], ['free', 'dependency'])

    # This feature is used to allow specific generators to run.
    # For example, QT tools can only be invoked when QT library
    # is used. In that case, qt will be in usage requirement
    # of the library.

feature.feature ('link', ['shared', 'static'], ['propagated'])
    feature.feature ('runtime-link', ['shared', 'static'], ['propagated'])
    feature.feature ('runtime-debugging', ['on', 'off'], ['propagated'])


    feature.feature ('optimization',  ['off', 'speed', 'space'], ['propagated'])
    feature.feature ('profiling', ['off', 'on'], ['propagated'])
    feature.feature ('inlining', ['off', 'on', 'full'], ['propagated'])

    feature.feature ('threading', ['single', 'multi'], ['propagated'])
    feature.feature ('rtti', ['on', 'off'], ['propagated'])
    feature.feature ('exception-handling', ['on', 'off'], ['propagated'])

    # Whether there is support for asynchronous EH (e.g. catching SEGVs).
    feature.feature ('asynch-exceptions', ['off', 'on'], ['propagated'])

    # Whether all extern "C" functions are considered nothrow by default.
    feature.feature ('extern-c-nothrow', ['off', 'on'], ['propagated'])

    feature.feature ('debug-symbols', ['on', 'off'], ['propagated'])
    feature.feature ('define', [], ['free'])
    feature.feature ('undef', [], ['free'])
    feature.feature ('include', [], ['free', 'path']) #order-sensitive
    feature.feature ('cflags', [], ['free'])
    feature.feature ('cxxflags', [], ['free'])
    feature.feature ('asmflags', [], ['free'])
    feature.feature ('linkflags', [], ['free'])
    feature.feature ('archiveflags', [], ['free'])
    feature.feature ('version', [], ['free'])

    feature.feature ('location-prefix', [], ['free'])

# property we need to list all the values to prevent unknown value errors. Both
    # set the default value to the current OS to account for the default use case of
    # building on the target OS.
    feature.feature('host-os', __os_names)
    feature.set_default('host-os', default_host_os())

    feature.feature('target-os', __os_names, ['propagated', 'link-incompatible'])
    feature.set_default('target-os', default_host_os())
    
    feature.feature ('toolset', [], ['implicit', 'propagated' ,'symmetric'])
    
    feature.feature ('stdlib', ['native'], ['propagated', 'composite'])
    
    feature.feature ('link', ['shared', 'static'], ['propagated'])
    feature.feature ('runtime-link', ['shared', 'static'], ['propagated'])
    feature.feature ('runtime-debugging', ['on', 'off'], ['propagated'])
    
    
    feature.feature ('optimization',  ['off', 'speed', 'space'], ['propagated'])
    feature.feature ('profiling', ['off', 'on'], ['propagated'])
    feature.feature ('inlining', ['off', 'on', 'full'], ['propagated'])
    
    feature.feature ('threading', ['single', 'multi'], ['propagated'])
    feature.feature ('rtti', ['on', 'off'], ['propagated'])
    feature.feature ('exception-handling', ['on', 'off'], ['propagated'])

    # Whether there is support for asynchronous EH (e.g. catching SEGVs).
    feature.feature ('asynch-exceptions', ['on', 'off'], ['propagated'])

    # Whether all extern "C" functions are considered nothrow by default.
    feature.feature ('extern-c-nothrow', ['off', 'on'], ['propagated'])

# This is internal feature which holds the paths of all dependency
    # dynamic libraries. On Windows, it's needed so that we can all
    # those paths to PATH, when running applications.
    # On Linux, it's needed to add proper -rpath-link command line options.
    feature.feature ('xdll-path', [], ['free', 'path'])
    
    #provides means to specify def-file for windows dlls.
    feature.feature ('def-file', [], ['free', 'dependency'])
    
    # This feature is used to allow specific generators to run.
    # For example, QT tools can only be invoked when QT library
    # is used. In that case, qt will be in usage requirement
    # of the library.
    feature.feature ('allow', [], ['free'])
    
    # The addressing model to generate code for. Currently a limited set only
    # specifying the bit size of pointers.
    feature.feature('address-model', ['16', '32', '64'], ['propagated', 'optional'])

    # Type of CPU architecture to compile for.
    feature.feature('architecture', [
        # x86 and x86-64
        'x86',

        # ia64
        'ia64',

        # Sparc
        'sparc',

# This is internal feature which holds the paths of all dependency
    # dynamic libraries. On Windows, it's needed so that we can all
    # those paths to PATH, when running applications.
    # On Linux, it's needed to add proper -rpath-link command line options.
    feature.feature ('xdll-path', [], ['free', 'path'])

    #provides means to specify def-file for windows dlls.
    feature.feature ('def-file', [], ['free', 'dependency'])

    # This feature is used to allow specific generators to run.
    # For example, QT tools can only be invoked when QT library
    # is used. In that case, qt will be in usage requirement
    # of the library.
    feature.feature ('allow', [], ['free'])

    # The addressing model to generate code for. Currently a limited set only
    # specifying the bit size of pointers.
    feature.feature('address-model', ['16', '32', '64'], ['propagated', 'optional'])

    # Type of CPU architecture to compile for.
    feature.feature('architecture', [
        # x86 and x86-64
        'x86',

        # ia64
        'ia64',

        # Sparc
        'sparc',

feature.feature ('inlining', ['off', 'on', 'full'], ['propagated'])
    
    feature.feature ('threading', ['single', 'multi'], ['propagated'])
    feature.feature ('rtti', ['on', 'off'], ['propagated'])
    feature.feature ('exception-handling', ['on', 'off'], ['propagated'])

    # Whether there is support for asynchronous EH (e.g. catching SEGVs).
    feature.feature ('asynch-exceptions', ['on', 'off'], ['propagated'])

    # Whether all extern "C" functions are considered nothrow by default.
    feature.feature ('extern-c-nothrow', ['off', 'on'], ['propagated'])

    feature.feature ('debug-symbols', ['on', 'off'], ['propagated'])
    feature.feature ('define', [], ['free'])
    feature.feature ('undef', [], ['free'])
    feature.feature ('include', [], ['free', 'path']) #order-sensitive
    feature.feature ('cflags', [], ['free'])
    feature.feature ('cxxflags', [], ['free'])
    feature.feature ('asmflags', [], ['free'])
    feature.feature ('linkflags', [], ['free'])
    feature.feature ('archiveflags', [], ['free'])
    feature.feature ('version', [], ['free'])
    
    feature.feature ('location-prefix', [], ['free'])

    feature.feature ('action', [], ['free'])

    
    # The following features are incidental, since
    # in themself they have no effect on build products.
    # Not making them incidental will result in problems in corner
    # cases, for example:

# cases, for example:
    #
    #    unit-test a : a.cpp : b ;
    #    lib b : a.cpp b ;
    #
    # Here, if  is not incidental, we'll decide we have two
    # targets for a.obj with different properties, and will complain.
    #
    # Note that making feature incidental does not mean it's ignored. It may
    # be ignored when creating the virtual target, but the rest of build process
    # will use them.
    feature.feature ('use', [], ['free', 'dependency', 'incidental'])
    feature.feature ('dependency', [], ['free', 'dependency', 'incidental'])
    feature.feature ('implicit-dependency', [], ['free', 'dependency', 'incidental'])

    feature.feature('warnings', [
        'on',         # Enable default/"reasonable" warning level for the tool.
        'all',        # Enable all possible warnings issued by the tool.
        'off'],       # Disable all warnings issued by the tool.
        ['incidental', 'propagated'])

    feature.feature('warnings-as-errors', [
        'off',        # Do not fail the compilation if there are warnings.
        'on'],        # Fail the compilation if there are warnings.
        ['incidental', 'propagated'])

    feature.feature('c++-template-depth',
        [str(i) for i in range(64,1024+1,64)] +
        [str(i) for i in range(20,1000+1,10)] +
        #   Maximum template instantiation depth guaranteed for ANSI/ISO C++
        # conforming programs.
        ['17'],