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<title>The Context Object</title>
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<td width="21"><h1></h1></td>
<td width="885"><font face="Verdana, Arial, Helvetica, sans-serif"><b><font size="6">The Context Object</font></b></font></td>
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<blockquote>
<p><a href="class_reference_context.html#introduction">Introduction</a><br>
<a href="class_reference_context.html#header_synopsis">Header
'wave/context.hpp' synopsis</a><br>
<a href="class_reference_context.html#public_typedefs">Public
Typedefs</a><br>
<a href="class_reference_context.html#template_parameters">Template
parameters</a><br>
<a href="class_reference_context.html#member_functions">Member
functions</a></p>
</blockquote>
<h2><b><a name="introduction"></a>Introduction</b></h2>
<p>The <tt>boost::wave::context<></tt> object is the main user visible object of the <tt>Wave</tt> library. It exists to generate the pair of iterators, which while
dereferenced return the preprocessed tokens. Additionally it is used to
control other aspects of the preprocessing, such as </p>
<blockquote>
<p><strong><img id="IMG1" src="theme/bullet.gif" height="13" width="13"></strong> include
search paths, which define, where to search for files to be included
with <tt>#include <...></tt> and <tt>#include "..."</tt> directives<br>
<strong><img src="theme/bullet.gif" height="13" width="13"> </strong>which macros to
predefine and which of the predefined macros to undefine<br>
<strong><img src="theme/bullet.gif" height="13" width="13"> </strong>several other options as
for instance to control, whether to enable several extensions to the
C++ Standard (as for instance variadics and placemarkers) or not.</p>
</blockquote>
<h2><b><a name="header_synopsis"></a>Header <a href="http://svn.boost.org/trac/boost/browser/trunk/boost/wave/cpp_context.hpp">wave/cpp_context.hpp</a> synopsis</b></h2>
<pre><span class="keyword">namespace</span> <span class="identifier">boost</span> {<br><span class="keyword">namespace</span> <span class="identifier">wave</span> { <br> <br> <span class="keyword"> struct</span> this_type {};<br><br> <span class="keyword">template</span> <<br> <span class="keyword">typename</span> Iterator, <span class="keyword">typename</span> LexIterator, <br> <span class="keyword">typename</span> InputPolicy, <span class="keyword">typename</span> ContextPolicy,<br> <span class="keyword">typename</span> Derived = this_type<br> > <br> <span class="keyword"> class</span> context <span class="special">:</span> <span class="keyword">public</span> InputPolicy <br> {<br> <span class="keyword">typedef</span> <unspecified> token_sequence_type;<br><br> <span class="keyword">public</span>: <br><br> <span class="keyword"> typedef</span> pp_iterator<context> iterator_type; <br> <span class="keyword">typedef</span> Token token_type;<br> <span class="keyword">typedef</span> <span class="keyword">typename</span> token_type::position_type position_type;<br> <span class="keyword">typedef</span> std::list<token_type> token_sequence_type;<br><br><span class="comment"> // constructor</span><br> <a href="class_reference_context.html#constructor">context</a>(Iterator<span class="keyword"> const</span> &first_, <br> Iterator <span class="keyword">const</span> &last_, <br> <span class="keyword">char const</span> *fname = <span class="string">"<Unknown>"</span>,<br> ContextPolicy <span class="keyword">const</span>& ctx_policy = ContextPolicy())<br><br> <span class="comment">// iterator interface</span><br> iterator_type <a href="class_reference_context.html#iterator_interface_begin">begin</a>() <span class="keyword">const</span>;<br> iterator_type <a href="class_reference_context.html#iterator_interface_begin">begin</a>(Iterator<span class="keyword"> const</span> &first, <br> Iterator <span class="keyword">const</span> &last) <span class="keyword">const</span>;<br> iterator_type <a href="class_reference_context.html#iterator_interface_end">end</a>() <span class="keyword">const</span>;<br><br> <span class="comment">// maintain include paths</span><br><span class="keyword"> bool</span> <a href="class_reference_context.html#add_include_path">add_include_path</a>(<span class="keyword">char const</span> *path_);<br> <span class="keyword">bool</span> <a href="class_reference_context.html#add_sysinclude_path">add_sysinclude_path</a>(<span class="keyword">char const</span> *path_);<br> <span class="keyword">void</span> <a href="class_reference_context.html#set_sysinclude_delimiter">set_sysinclude_delimiter</a>();<br> <br> size_t <a href="class_reference_context.html#get_iteration_depth">get_iteration_depth</a>() <span class="keyword">const</span>;<br><br> <span class="comment"> // maintain defined macros</span><br> <span class="keyword">template</span> <<span class="keyword">typename</span> String><br><span class="keyword"> bool</span> <a href="class_reference_context.html#add_macro_definition">add_macro_definition</a>(<span class="keyword">String</span> macrostring, <br> <span class="keyword"> bool</span> is_predefined = <span class="keyword">false</span>);<br> <span class="keyword">template</span> <<span class="keyword">typename</span> String><br><span class="keyword"></span> <span class="keyword">bool</span> add_macro_definition(StringT <span class="keyword">const</span> &name, <br> position_type <span class="keyword">const</span>& pos, <span class="keyword">bool</span> has_params, <br> std::vector<token_type> &parameters, <br> token_sequence_type &definition, <br> <span class="keyword">bool</span> is_predefined = <span class="keyword">false</span>)<br><br> <span class="keyword">template</span> <<span class="keyword">typename</span> String><br> <span class="keyword">bool</span> <a href="class_reference_context.html#is_defined_macro">is_defined_macro</a>(<span class="keyword">String const</span> &name) <span class="keyword">const</span>;<br> <span class="keyword">template</span> <<span class="keyword">typename</span> String><br> <span class="keyword">bool</span> <a href="class_reference_context.html#remove_macro_definition">remove_macro_definition</a>(String<span class="keyword"> const</span> &name, <br> <span class="keyword"> bool</span> even_predefined = <span class="keyword">false</span>);<br> <span class="keyword">void</span> <a href="class_reference_context.html#reset_macro_definitions">reset_macro_definitions</a>();<br> <span class="keyword">template</span> <<span class="keyword">typename</span> String><br> <span class="keyword"> bool</span> <a href="class_reference_context.html#get_macro_definition">get_macro_definition</a>(<br> <span class="keyword"> </span>String<span class="keyword"> const</span> &name, <span class="keyword">bool</span> &is_function_style, <span class="keyword"><br> bool</span> &is_predefined, position_type &pos, <br> std::vector<token_type> &parameters, <br> token_sequence_type &definition) <span class="keyword">const</span>; <br><br> <span class="keyword">typedef</span> <unspecified> macromap_type;<br> <span class="keyword">typedef</span> typename macromap_type::name_iterator name_iterator;<br> <span class="keyword">typedef</span> typename macromap_type::const_name_iterator const_name_iterator;<br><br> name_iterator <a href="class_reference_context.html#macro_names_iterators">macro_names_begin</a>();<br> name_iterator <a href="class_reference_context.html#macro_names_iterators">macro_names_end</a>();<br> const_name_iterator <a href="class_reference_context.html#macro_names_iterators">macro_names_begin</a>() <span class="keyword">const</span>;<br> const_name_iterator <a href="class_reference_context.html#macro_names_iterators">macro_names_end</a>() <span class="keyword">const</span>;<br><br> <span class="comment">// other options</span><br><span class="keyword"> void</span> <a href="class_reference_context.html#language_support">set_language</a>(language_support enable);<br> language_support <a href="class_reference_context.html#language_support">get_language</a>() <span class="keyword">const</span>;<br><br><span class="keyword"> void</span> <a href="class_reference_context.html#set_max_include_nesting_depth">set_max_include_nesting_depth</a>(std::size_t new_depth);<br> size_t <a href="class_reference_context.html#set_max_include_nesting_depth">get_max_include_nesting_depth</a>() <span class="keyword">const</span>;<br><br><span class="comment"> // get the Wave version information </span><br><span class="keyword"> static std::string</span> <a href="class_reference_context.html#get_version">get_version</a>();<br> <span class="keyword">static std::string</span> <a href="class_reference_context.html#get_version">get_version_string</a>();<br> };<br><br>} <span class="comment">// namespace wave</span><br>} <span class="comment">// namespace boost</span></pre>
<h2><b><a name="template_parameters"></a>Template
parameters</b></h2>
<p>The <tt>boost::wave::context</tt> object has
three template parameters to specify the concrete behaviour of its
operation. The following table describes these with more detail.</p>
<table align="center" border="0" width="90%">
<tbody>
<tr>
<td colspan="2" class="table_title"><b>Template
parameters required for the <tt>boost::wave::context</tt> class </b></td>
</tr>
<tr>
<td class="table_cells" width="32%"><code>Iterator</code></td>
<td class="table_cells" width="68%"><p>The type of the underlying iterator, through which the
input stream is accessed. <br>
This should be at least an <tt>forward_iterator</tt> type
iterator.</p></td>
</tr>
<tr>
<td class="table_cells"><code>LexIterator</code></td>
<td class="table_cells"><p>The type of the lexer type to be used by the <tt>Wave</tt> library to identify tokens in the input stream.</p></td>
</tr>
<tr>
<td class="table_cells"><code>InputPolicy</code></td>
<td class="table_cells"><p>The type of the input policy class, which allows to
customize the behaviour of the Wave library and the type of the
iterators to use, when it comes to including and opening an included
file.</p></td>
</tr>
<tr>
<td class="table_cells"><code>ContextPolicy</code></td>
<td class="table_cells"><p>The type of the context policy class, which allows to
customize different aspects of the behaviour of the preprocessing. The
requirements of this policy and the available customization points
provided by this policy are described <a href="class_reference_ctxpolicy.html">here</a>.
</p></td>
</tr>
<tr class="table_cells">
<td class="table_cells"><code>Derived</code></td>
<td><p>The type of the type being derived from the context type (if
any). This template parameter is optional and defaults to 'this_type',
which means that the context type will be used assuming no derived type exists. <br>
</p></td>
</tr>
</tbody>
</table>
<p>For further information about the lexer type to use, please
refer to the <a href="class_reference_lexer.html">The
Lexer Interface </a>.</p>
<p>If the template parameter <tt>InputPolicy</tt> is
omitted, the template <tt>boost::wave::iteration_context_policies::load_file_to_string</tt> is used. For further information about the input policy, please refer
to the topic <a href="class_reference_inptpolcy.html">The
Input Policy</a>.</p>
<p>If the template parameter ContextPolicy is omitted, the <tt>boost::wave::context_policies::eat_whitespace</tt> policy type is used, implementing certain basic preprocessing hooks
needed for normal (default) execution. For further information about
the context policy, please refer to the topic <a href="class_reference_ctxpolicy.html">The Context Policy</a>. </p>
<h2><a name="public_typedefs"></a>Public
Typedefs</h2>
<p>The <tt>boost::wave::context</tt> template
defines the following public typedefs, which may be useful while using
this class:</p>
<table align="center" border="0" width="90%">
<tbody>
<tr>
<td colspan="2" class="table_title"><b>Public
typedef's defined by the <tt>boost::wave::context</tt> class </b></td>
</tr>
<tr>
<td class="table_cells"><code>iterator_type</code></td>
<td class="table_cells"><p>The <tt>Iterator</tt> template parameter
provided, while the <tt>context</tt> class was
instantiated. </p></td>
</tr>
<tr>
<td class="table_cells"><code>lex_type</code></td>
<td class="table_cells"><p>The <tt>LexIterator</tt> template parameter
provided, while the <tt>context</tt> class was
instantiated. </p></td>
</tr>
<tr>
<td class="table_cells" width="32%"><code>token_type</code></td>
<td class="table_cells" width="68%"><p>The token type, which is returned by the <tt>context</tt> generated iterators. This type is taken from the <tt>LexIterator</tt> template parameter provided, whicle the <tt>context</tt> class was instantiated.</p></td>
</tr>
<tr>
<td class="table_cells"><code>input_policy_type</code></td>
<td class="table_cells"><p>The <tt>InputPolicy</tt> template parameter
provided, while the <tt>context</tt> class was
instantiated. </p></td>
</tr>
<tr>
<td class="table_cells"><code>context_policy_type</code></td>
<td class="table_cells"><p>The <tt>ContextPolicy</tt> template
parameter provided, while the <tt>context</tt> class was
instantiated. </p></td>
</tr>
<tr>
<td class="table_cells"><code>position_type</code></td>
<td class="table_cells"><p>The type of the position information contained in every
returned token, which describes the point, at which the given token was
recognised. </p></td>
</tr>
</tbody>
</table>
<h2><b><a name="member_functions"></a>Member
functions</b></h2>
<p><b><a name="constructor" id="constructor"></a>Constructor</b></p>
<pre> context(Iterator <span class="keyword">const</span> &first, <br> Iterator <span class="keyword">const</span> &last, <span class="keyword">char</span> <span class="keyword">const</span> *filename, <br> ContextPolicy <span class="keyword">const</span>& ctx_policy);</pre>
<p>Constructs a context object on top of the input stream given
by the pair of auxilliary iterators <tt>[first, last)</tt>.
The iterators should be at least <tt>forward_iterator</tt> type iterators. The filename parameter is to be supplied for
informational purposes only. This string is used for indicating the
token positions inside the input stream, it is not validated against
the file system. If the filename parameter is not given it defaults to <span class="copyright">"<Unknown>"</span>. If
the ctx_policy parameter isn't supplied it defaults to a default
constructed <tt>ContextPolicy</tt> object. </p>
<p>Additionally the macro symbol table is filled with the
predefined macros and the current reference directory is set to the
path of the given filename. If this filename does not reference valid
file system item, the current reference directory is set to the current
system directory. (The current reference directory is the file system
path, which is used as the target directory during the processing of <tt>#include "..."</tt> directives).</p>
<h3>Iterator interface</h3>
<p>The pair of iterators returned by the <tt>context::begin</tt> and <tt>context::end</tt> functions is the main interface
for accessing the preprocessed tokens from the preprocessor engine.
While iterating over the given iterator range <tt>[begin, end)</tt> there are returned the preprocessed C++ tokens, which are generated on
the fly from the underlying input stream. The returned iterators are
conceptually of <tt>forward_iterator</tt> type.</p>
<p><b><a name="iterator_interface_begin"></a></b><b>begin</b></p>
<pre> iterator_type begin();<br> iterator_type begin(Iterator <span class="keyword">const</span> &first,<br> Iterator <span class="keyword">const</span> &last, <span class="keyword"></span>);</pre>
<blockquote>
<p>Initializes and returns the starting iterator for the
preprocessed token stream. The iterator pair given by the parameters <tt>[first, last)</tt> specifies the input sequence to preprocess. The first version of this
function uses the iinput stream as specified by the constructor. </p>
</blockquote>
<p><b><a name="iterator_interface_end" id="iterator_interface_end"></a></b><b>end</b></p>
<pre> iterator_type end() <span class="keyword">const</span>;</pre>
<blockquote>
<p>Initializes and returns the end of stream iterator to
compare with for detecting the end of the preprocessed token stream.</p>
</blockquote>
<h3>Maintain include paths</h3>
<p>The <tt>Wave</tt> library maintains two separate
search paths for include files. A search path for user include files
and a search path for system include files. Any directories specified
with the <a href="#add_include_path">add_include_path()</a> function before the function <a href="class_reference_context.html#set_sysinclude_delimiter">set_sysinclude_delimiter()</a> is called are searched only for the case of <tt>#include "..."</tt> directives, they are not searched for <tt>#include <file></tt> directives. I.e. these directories are added to the user include search
path. </p>
<p>If additional directories are specified with the <a href="#add_include_path">add_include_path()</a> function after a call to the function <a href="class_reference_context.html#set_sysinclude_delimiter">set_sysinclude_delimiter()</a>,
these directories are searched for all <tt>#include</tt> directives. I.e. these directories are added to the system include
search path.</p>
<p>In addition, a call to the function <a href="class_reference_context.html#set_sysinclude_delimiter">set_sysinclude_delimiter()</a> inhibits the use of the current reference directory as the first search
directory for <tt>#include "..."</tt> directives.
Therefore, the current reference directory is searched only, if it is
requested explicitly with a call to the function <a href="#add_include_path">add_include_path(".")</a>. </p>
<p>Callig both functions, the <a href="class_reference_context.html#set_sysinclude_delimiter">set_sysinclude_delimiter()</a> and <a href="#add_include_path">add_include_path(".")</a> allows you to control precisely, which directories are searched before
the current one and which are searched after.</p>
<p>These functions are modelled after the command line behaviour
implemented by the popular gcc compiler.<br>
</p>
<p><a name="add_include_path"></a><b>add_include_path</b></p>
<pre> <span class="keyword"> bool</span> add_include_path(<span class="keyword">char const</span> *path);<br>
</pre>
<blockquote>
<p>Adds the given file system path to the user include search
paths. After a call to the <a href="class_reference_context.html#set_sysinclude_delimiter">set_sysinclude_delimiter()</a> this function adds the given file system path to the system include
search paths. Note though, that the given path is validated against the
file system. </p>
<p>If the given path string does not form a name of a valid
file system directory item, the function returns <tt>false</tt>.
If the given path was successfully added to the include search paths in
question, the function returns <tt>true</tt>.</p>
</blockquote>
<p><a name="add_sysinclude_path"></a><b>add_sysinclude_path</b></p>
<pre> <span class="keyword">bool</span> add_sysinclude_path(<span class="keyword">char const</span> *path);</pre>
<blockquote>
<p>Adds the given file system path to the system include search
paths. This function operates on the system include search path
regardless of the mode of operation of the <a href="#add_include_path">add_include_path()</a>. Note
though, that the given path is validated against the file system.</p>
<p>If the given path string does not form a name of a valid
file system directory item, the function returns <tt>false</tt>.
If the given path was successfully added to the system include search
paths, the function returns <tt>true</tt>.</p>
</blockquote>
<p><a name="set_sysinclude_delimiter"></a><b>set_sysinclude_delimiter</b></p>
<pre> <span class="keyword"> void</span> set_sysinclude_delimiter();</pre>
<blockquote>
<p>Switches the mode, how the <a href="#add_include_path">add_include_path()</a> function operates. By default the given file system path is added to
the user include search paths. After calling this function a subsequent
call to the <a href="#add_include_path">add_include_path()</a> adds the given file system path to the system include search paths.
Additionally it inhibits the the use of the current reference directory
as the first search directory for <tt>#include "..."</tt> directives.</p>
</blockquote>
<p><a name="get_iteration_depth"></a><b>get_iteration_depth</b></p>
<pre> size_t get_iteration_depth() <span class="keyword">const</span>;</pre>
<blockquote>
<p>Returns the actual include iteration depth, i.e. the current
number of include levels to be poped from the include iteration
context, before the main (topmost) iteration context is reached.</p>
</blockquote>
<h3>Maintain defined macros</h3>
<p><a name="add_macro_definition"></a><b>add_macro_definition</b></p>
<pre><span class="keyword"> bool</span> add_macro_definition(<br> <span class="keyword"> std::string</span> macrostring, <span class="keyword">bool</span> is_predefined); <br>
</pre>
<blockquote>
<p>Adds a new macro definition to the macro symbol table. The
parameter <tt>macrostring</tt> should contain the macro to
define in the command line format, i.e. something like <tt>MACRO(x)=definition</tt>.
The following table describes this format in more detail. The parameter <tt>is_predefined</tt> should be true while defining
predefined macros, i.e. macros, which are not undefinable with an <tt>#undef</tt> directive from inside the preprocessed input stream. If this parameter
is not given, it defaults to <tt>false</tt>.</p>
<table align="center" border="0" width="90%">
<tbody>
<tr>
<td colspan="2" class="table_title"><b>Summary
of possible formats for defining macros </b></td>
</tr>
<tr>
<td class="table_cells" width="32%"><code>MACRO</code></td>
<td class="table_cells" width="68%"><code>define <tt>MACRO</tt> as 1</code></td>
</tr>
<tr>
<td class="table_cells"><code>MACRO=</code></td>
<td class="table_cells"><code>define <tt>MACRO</tt> as nothing (empty)</code></td>
</tr>
<tr>
<td class="table_cells"><code>MACRO=definition</code></td>
<td class="table_cells"><code>define <tt>MACRO</tt> as <tt>definition</tt></code></td>
</tr>
<tr>
<td class="table_cells" width="32%"><code>MACRO(x)</code></td>
<td class="table_cells" width="68%"><code>define <tt>MACRO(x)</tt> as 1</code></td>
</tr>
<tr>
<td class="table_cells"><code>MACRO(x)=</code></td>
<td class="table_cells"><code>define <tt>MACRO(x)</tt> as nothing (empty)</code></td>
</tr>
<tr>
<td class="table_cells"><code>MACRO(x)=definition</code></td>
<td class="table_cells"><code>define <tt>MACRO(x)</tt> as <tt>definition</tt></code></td>
</tr>
</tbody>
</table>
<p>The function returns <tt>false</tt>, if the
macro to define already was defined and the new definition is
equivalent to the existing one, it returns true, if the new macro was
successfully added to the macro symbol table.</p>
<p>If the given macro definition resembles a redefinition and
the new macro is not identical to the already defined macro (in the
sense defined by the C++ Standard), the function throws a corresponding <tt>preprocess_exception</tt>.</p>
</blockquote>
<p><a name="is_defined_macro"></a><b>is_defined_macro</b></p>
<pre> <span class="keyword"> template</span> <<span class="keyword">typename</span> String><br> <span class="keyword">bool</span> is_defined_macro(String <span class="keyword">const</span> &name) <span class="keyword">const</span>; </pre>
<blockquote>
<p>Returns, if a macro with the given <tt>name</tt> is defined, i.e. if it is contained in the macro symbol table.</p>
</blockquote>
<p><strong><a name="get_macro_definition"></a>get_macro_definition</strong></p>
<pre> <span class="keyword"> template</span> <<span class="keyword">typename</span> String><br> <span class="keyword">bool</span> get_macro_definition(<br> <span class="keyword"> </span>String<span class="keyword"> const</span> &name, <span class="keyword">bool</span> &is_function_style, <span class="keyword"><br> bool</span> &is_predefined, position_type &pos, <br> std::vector<token_type> &parameters, <br> token_sequence_type &definition) <span class="keyword">const</span>; </pre>
<blockquote>
<p>Allows to retrieve all information known with regard to a
macro definition. The parameter <tt>name</tt> specifies
the name of the macro the information should be returned for. The
parameters <tt>is_function_style</tt> and <tt>is_predefined</tt> return, whether the macro has been defined as a function style macro or
as a predefined macro resp. The parameter <tt>pos</tt> will contain the position the macro was defined at. The parameter <tt>parameters</tt> will contain the names of the parameters the macro was defined with and
the parameter <tt>definition</tt> will contain the token
sequence for the definition (macro body).</p>
<p>The function returns <tt>true</tt> is the macro
was defined and the requested information has been successfully
retrieved, <tt>false</tt> otherwise.</p>
</blockquote>
<p><a name="remove_macro_definition"></a><b>remove_macro_definition</b></p>
<pre><span class="keyword"> </span> <span class="keyword"> template</span> <<span class="keyword">typename</span> String><br><span class="keyword"> bool</span> remove_macro_definition(<br> String<span class="keyword"> const</span> &name, <span class="keyword">bool</span> even_predefined); </pre>
<blockquote>
<p>Removes the definition of the macro with the given <tt>name</tt> from the macro symbol table. This operation is equivalent to an <tt>#undef</tt> directive with this <tt>name</tt> executed from within the
input stream. If the parameter <tt>even_predefined</tt> is <tt>true</tt>, then the macro is removed from the macro
symbol table even, if it is defined as a predefined macro. </p>
<p>Note though, that the following macros are <b>not</b> undefinable in any case: <tt>__FILE__</tt>, <tt>__LINE__</tt>, <tt>__DATE__</tt>, <tt>__TIME__</tt>, <tt>__cplusplus</tt>, <tt>__STDC__</tt>. If the parameter <tt>even_predefined</tt> is not given, it defaults to <tt>false</tt>.</p>
<p>The function returns <tt>false</tt>, if the
macro to undefine was not defined and returns <tt>true</tt> otherwise.</p>
<p>If the macro to remove may not be undefined (it is a
predefined macro and the parameter <tt>even_predefined</tt> is set to <tt>false</tt> or it is one of the mentioned not
undefinable macros above) the function throws a <tt>preprocess_exception</tt>.</p>
</blockquote>
<p><a name="reset_macro_definitions"></a><b>reset_macro_definitions</b></p>
<pre><span class="keyword"> void</span> reset_macro_definitions(); </pre>
<blockquote>
<p>Resets the macro symbol table to it's initial state, i.e.
undefines all user defined macros and inserts the internal predefined
macros as described <a href="predefined_macros.html">here</a>.</p>
</blockquote>
<p><a name="macro_names_iterators"></a><b>macro_names_begin,
macro_names_end </b></p>
<pre> name_iterator <a href="class_reference_context.html#macro_names_iterators">macro_names_begin</a>();<br> name_iterator <a href="class_reference_context.html#macro_names_iterators">macro_names_end</a>();<br> const_name_iterator <a href="class_reference_context.html#macro_names_iterators">macro_names_begin</a>() <span class="keyword">const</span>;<br> const_name_iterator <a href="class_reference_context.html#macro_names_iterators">macro_names_end</a>() <span class="keyword">const</span>;<br>
</pre>
<blockquote>
<p>The <tt>macro_names_begin</tt> and <tt>macro_names_end</tt> functions return iterators allowing to iterate on the names of all
defined macros.</p>
</blockquote>
<h3><a name="get_version"></a>Get Version
information</h3>
<p><b>get_version</b></p>
<pre><span class="keyword"> </span><span class="keyword"> static std::string</span> get_version(); </pre>
<blockquote>
<p>Returns a string containing the current Wave version
formatted as <span class="string">0xvvrsbbbb</span> (this is a string representation of the equivalent hexadecimal number),
where <span class="literal">'vv'</span> is the
version number, <span class="literal">'r'</span> the release number, <span class="literal">'s'</span> the subrelease number and <span class="literal">'bbbb'</span> the build number. A possible return value looks like <span class="literal">0x00910454</span>. The returned value
is the same as is inserted in the preprocessed token stream, when the
predefined macro <tt>__WAVE_VERSION__</tt> is expanded.</p>
</blockquote>
<p><b>get_version_str</b></p>
<pre><span class="keyword"> </span><span class="keyword"> static std::string</span> get_version_str(); </pre>
<blockquote>
<p>Returns a string containing the current Wave version
formatted as <span class="string">"v.rr.ss.bbbb"</span>,
where <span class="literal">'v'</span> is the
version number, <span class="literal">'rr'</span> the release number, <span class="literal">'ss'</span> the subrelease number and <span class="literal">'bbbb'</span> the build number. A possible return value looks like <span class="literal">"0.9.1.454"</span>. The returned value
is the same as it will be inserted in the preprocessed token stream,
when the predefined macro <tt>__WAVE_VERSION_STR__</tt> is
expanded.</p>
</blockquote>
<h3>Control extended options</h3>
<p><a name="language_support"></a>set_language<br>
get_language</p>
<pre><span class="keyword"> void</span> set_language(<span class="keyword">language_support</span> language, <br> <span class="keyword">bool</span> reset_macros = <span class="keyword">true</span>);<br> <span class="keyword">language_support</span> get_language() <span class="keyword">const</span>;</pre>
<blockquote>
<p>This functions allows to specify the language mode, in which
the <tt>Wave</tt> library should work. The possible
language modes are defined by the enumerated type <tt>language_support</tt>:</p>
<pre> <span class="keyword">enum</span> language_support {<br> <span class="comment">// support flags for C++98</span><br> support_normal = 0x01,<br> support_cpp = support_normal,<br><span class="comment"><br> // support flags for C99</span><br> support_option_long_long = 0x02,<br> support_option_variadics = 0x04,<br> support_c99 = support_option_variadics | support_option_long_long | 0x08,<br><span class="comment"><br> // the mask for the main language settings</span><br> support_option_mask = 0xFF80,<br><br><span class="comment"> // additional fine tuning of the general behavior</span><br> support_option_insert_whitespace = 0x0080,<br> support_option_preserve_comments = 0x0100,<br> support_option_no_character_validation = 0x0200,<br> support_option_convert_trigraphs = 0x0400,<br> support_option_single_line = 0x0800,<br> support_option_prefer_pp_numbers = 0x1000,<br> support_option_emit_line_directives = 0x2000,<br> support_option_include_guard_detection = 0x4000,<br> support_option_emit_pragma_directives = 0x8000<br> };</pre>
<p>When used with <tt>support_option_variadics</tt> the support for variadics, placemarkers and the <tt>operator _Pragma()</tt> is enabled in normal C++ mode. When used with the <tt>support_option_long_long</tt> the support for long long suffixes is enabled in C++ mode. </p>
<p>The <tt>support_c99</tt> switches on the C99
language support, which enables variadics, placemarkers, the <tt>operator _Pragma</tt> and long long suffixes by default. Additionally it disables the C++
specific tokens such as <tt>'->*'</tt>, <tt>'.*'</tt>, <tt>'::'</tt> etc. </p>
<p>The <tt>support_option_...</tt> values are to
be used in conjunction with the main language settings (<tt>support_normal</tt> and <tt>support_c99</tt>) . </p>
<ul>
<li>If the <tt>support_option_insert_whitespace</tt> flag is set, the <tt>Wave</tt> library inserts
additional whitespace between tokens where the concatenated string
representation of the two tokens would form another valid C++ token.
This is very importatnt to avoid mis-interpretations of the generated
output if it is going to be processed by a C++ compiler afterwards.
</li>
<li>If the <tt>support_option_preserve_comments</tt> flag is set, the <tt>Wave</tt> library preserves almost
all comments in the source code. The only comments not preserved are
those contained inside macro definitions. If this flag is not set all
comments are replaced by a single space. </li>
<li>If the <tt>support_option_no_character_validation</tt> flag is set , the <tt>Wave</tt> library does not validate
universal character literals (given in the form of <tt>'u1234'</tt> or <tt>'U12345678'</tt>) to be in the allowed value range.
This flag is merely used for internal purposes by the testing framework
and will be rarely used by a user of the library.</li>
<li>If the <tt>support_option_convert_trigraphs</tt> flag is set, the <tt>Wave</tt> library replaces all
occurences of trigraph characters with their non-trigraph character
sequence (i.e. <tt>'??='</tt> is replaced by <tt>'#'</tt> etc.) . By default no replacement is performed. </li>
<li>If the <tt>support_option_single_line</tt> flag is set, the <tt>Wave</tt> library will now reprot an
error if the last line of the processed input is not terminated by a
new line. This flag is merely used for internal purposes by the testing
framework and will be rarely used by a user of the library.</li>
<li>If the <tt>support_option_prefer_pp_numbers</tt> flag is set, the <tt>Wave</tt> library is instructed to
correctly identify pp-number's in the input stream. These get
recognized into 'normal' number tokens before they get returned to the
calling application. The flag is set by default and is used merely for
internal purposes and will be rarely reset by a user of the library. </li>
<li>If the <span class="keyword">support_option_emit_line_directives</span> flag is set, the <tt>Wave</tt> library will emit <span class="preprocessor">#line</span> directives in the
generated token stream, if appropriate. This flag is set by default, to
prevent the library from generating <span class="preprocessor">#line</span> directives it must be reset explicitely. </li>
<li>If the <span class="keyword">support_option_include_guard_detection</span> flag is set, the <tt>Wave</tt> library will try to
automatically identify include guards during the processing of a
included file. Files which contained include guards are handled as if
they contained a #pragma once, i.e. these files wonn#t be opened twice,
even if specified in a second <span class="preprocessor">#include</span> statement. </li>
</ul>
<blockquote>
<p>During this process the library will recognize two forms
of include guards:</p>
<pre> <span class="preprocessor">#ifndef</span> INCLUDE_GUARD_MACRO<br> <span class="preprocessor">#define</span> INCLUDE_GUARD_MACRO<br> ...<br> <span class="preprocessor">#endif</span><br>or<br><span class="preprocessor"> #if</span> !defined(INCLUDE_GUARD_MACRO)<br> <span class="preprocessor">#define</span> INCLUDE_GUARD_MACRO<br> ...<br> <span class="preprocessor">#endif</span></pre>
<p> Note, that the parenthesis in the second form are
optional (i.e. <tt>!defined INCLUDE_GUARD_MACRO</tt> will
work as well). The code allows for any whitespace, newline and single
'#' tokens before the <span class="preprocessor">#if</span>/<span class="preprocessor">#ifndef</span> and after the
final <span class="preprocessor">#endif</span> for
the include guard to be recognized.</p>
<p>This flag is on by default, so if you do not want the
library to automatically reconize include guards you will need to reset
this explicitely. </p>
</blockquote>
<ul>
<li>If the <tt>support_option_emit_pragma_directives</tt> flag is set, the <tt>Wave</tt> library will emit all
unknown <span class="preprocessor">#pragma</span> directives to the output. This suport option will be recognized only if
the <tt>BOOST_WAVE_EMIT_PRAGMA_DIRECTIVES</tt> is defined
during compilation to a value not equal to zero (see <a href="compiletime_config.html">here</a> for more
information). </li>
</ul>
<p><strong> </strong>If the parameter <tt>reset_macros</tt> is true the <tt>set_language</tt> function internally
resets the list of defined macros, so please be careful not to call it
after you have defined your own macros already. </p>
</blockquote>
<p><a name="set_max_include_nesting_depth" id="set_max_include_nesting_depth"></a>set_max_include_nesting_depth<br>
get_max_include_nesting_depth</p>
<pre><span class="keyword"> void</span> set_max_include_nesting_depth(size_t new_depth); <br> size_t get_max_include_nesting_depth() <span class="keyword">const</span>;</pre>
<blockquote>
<p>This functions allow to set or to get the maximal possible
include file nesting depth supported by the <tt>Wave</tt> library. The initial value for this is determined by the preprocessing
constant <tt>WAVE_MAX_INCLUDE_LEVEL_DEPTH</tt> (see <a href="compiletime_config.html">here</a>).</p>
</blockquote>
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<p class="copyright">Copyright © 2003-2010
Hartmut Kaiser<br>
<br>
<font size="2">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) </font> </p>
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<!-- #BeginDate format:fcAm1m -->Sunday, October 12, 2008 20:14<!-- #EndDate -->
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