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Update libstdc++ documentation for Support and Diagnostics clauses

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* doc/xml/manual/diagnostics.xml: Update list of headers that define
	exception classes.
	* doc/xml/manual/support.xml: Rewrite advice around NULL. Rewrite
	section about new/delete overloads. Improve section on verbose
	terminate handler.
	* doc/html/*: Regenerate.

From-SVN: r271782
This commit is contained in:
Jonathan Wakely 2019-05-30 16:47:32 +01:00 committed by Jonathan Wakely
parent 30f78ec756
commit 01b3b9e39f
10 changed files with 440 additions and 178 deletions
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2019-05-30 Jonathan Wakely <jwakely@redhat.com>
* doc/xml/manual/diagnostics.xml: Update list of headers that define
exception classes.
* doc/xml/manual/support.xml: Rewrite advice around NULL. Rewrite
section about new/delete overloads. Improve section on verbose
terminate handler.
* doc/html/*: Regenerate.
* doc/xml/manual/status_cxx2020.xml: Add feature-test macro for
P0811R3. Change status of P1353R0.
* doc/html/*: Regenerate.

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</a></span></dt><dd><dl><dt><span class="chapter"><a href="manual/support.html">4.
Support
</a></span></dt><dd><dl><dt><span class="section"><a href="manual/support.html#std.support.types">Types</a></span></dt><dd><dl><dt><span class="section"><a href="manual/support.html#std.support.types.fundamental">Fundamental Types</a></span></dt><dt><span class="section"><a href="manual/support.html#std.support.types.numeric_limits">Numeric Properties</a></span></dt><dt><span class="section"><a href="manual/support.html#std.support.types.null">NULL</a></span></dt></dl></dd><dt><span class="section"><a href="manual/dynamic_memory.html">Dynamic Memory</a></span></dt><dt><span class="section"><a href="manual/termination.html">Termination</a></span></dt><dd><dl><dt><span class="section"><a href="manual/termination.html#support.termination.handlers">Termination Handlers</a></span></dt><dt><span class="section"><a href="manual/termination.html#support.termination.verbose">Verbose Terminate Handler</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="manual/diagnostics.html">5.
</a></span></dt><dd><dl><dt><span class="section"><a href="manual/support.html#std.support.types">Types</a></span></dt><dd><dl><dt><span class="section"><a href="manual/support.html#std.support.types.fundamental">Fundamental Types</a></span></dt><dt><span class="section"><a href="manual/support.html#std.support.types.numeric_limits">Numeric Properties</a></span></dt><dt><span class="section"><a href="manual/support.html#std.support.types.null">NULL</a></span></dt></dl></dd><dt><span class="section"><a href="manual/dynamic_memory.html">Dynamic Memory</a></span></dt><dd><dl><dt><span class="section"><a href="manual/dynamic_memory.html#std.support.memory.notes">Additional Notes</a></span></dt></dl></dd><dt><span class="section"><a href="manual/termination.html">Termination</a></span></dt><dd><dl><dt><span class="section"><a href="manual/termination.html#support.termination.handlers">Termination Handlers</a></span></dt><dt><span class="section"><a href="manual/termination.html#support.termination.verbose">Verbose Terminate Handler</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="manual/diagnostics.html">5.
Diagnostics
</a></span></dt><dd><dl><dt><span class="section"><a href="manual/diagnostics.html#std.diagnostics.exceptions">Exceptions</a></span></dt><dd><dl><dt><span class="section"><a href="manual/diagnostics.html#std.diagnostics.exceptions.api">API Reference</a></span></dt><dt><span class="section"><a href="manual/diagnostics.html#std.diagnostics.exceptions.data">Adding Data to <code class="classname">exception</code></a></span></dt></dl></dd><dt><span class="section"><a href="manual/errno.html">Use of errno by the library</a></span></dt><dt><span class="section"><a href="manual/concept_checking.html">Concept Checking</a></span></dt></dl></dd><dt><span class="chapter"><a href="manual/utilities.html">6.

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Diagnostics
<a id="id-1.3.4.3.1.1.1" class="indexterm"></a>
</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions">Exceptions</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.api">API Reference</a></span></dt><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.data">Adding Data to <code class="classname">exception</code></a></span></dt></dl></dd><dt><span class="section"><a href="errno.html">Use of errno by the library</a></span></dt><dt><span class="section"><a href="concept_checking.html">Concept Checking</a></span></dt></dl></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="std.diagnostics.exceptions"></a>Exceptions</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="std.diagnostics.exceptions.api"></a>API Reference</h3></div></div></div><p>
All exception objects are defined in one of the standard header
files: <code class="filename">exception</code>,
<code class="filename">stdexcept</code>, <code class="filename">new</code>, and
<code class="filename">typeinfo</code>.
Most exception classes are defined in one of the standard headers
<code class="filename">&lt;exception&gt;</code>,
<code class="filename">&lt;stdexcept&gt;</code>,
<code class="filename">&lt;new&gt;</code>, and
<code class="filename">&lt;typeinfo&gt;</code>.
The C++ 2011 revision of the standard added more exception types
in the headers
<code class="filename">&lt;functional&gt;</code>,
<code class="filename">&lt;future&gt;</code>,
<code class="filename">&lt;regex&gt;</code>, and
<code class="filename">&lt;system_error&gt;</code>.
The C++ 2017 revision of the standard added more exception types
in the headers
<code class="filename">&lt;any&gt;</code>,
<code class="filename">&lt;filesystem&gt;</code>,
<code class="filename">&lt;optional&gt;</code>, and
<code class="filename">&lt;variant&gt;</code>.
</p><p>
The base exception object is <code class="classname">exception</code>,
located in <code class="filename">exception</code>. This object has no
<code class="classname">string</code> member.
All exceptions thrown by the library have a base class of type
<code class="classname">std::exception</code>,
defined in <code class="filename">&lt;exception&gt;</code>.
This type has no <code class="classname">std::string</code> member.
</p><p>
Derived from this are several classes that may have a
<code class="classname">string</code> member: a full hierarchy can be
<code class="classname">std::string</code> member. A full hierarchy can be
found in the source documentation.
</p><p>
Full API details.
</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="std.diagnostics.exceptions.data"></a>Adding Data to <code class="classname">exception</code></h3></div></div></div><p>
The standard exception classes carry with them a single string as
data (usually describing what went wrong or where the 'throw' took

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Support
</th><td width="20%" align="right"> <a accesskey="n" href="termination.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="std.support.memory"></a>Dynamic Memory</h2></div></div></div><p>
There are six flavors each of <code class="function">new</code> and
<code class="function">delete</code>, so make certain that you're using the right
ones. Here are quickie descriptions of <code class="function">new</code>:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
single object form, throwing a
<code class="classname">bad_alloc</code> on errors; this is what most
people are used to using
</p></li><li class="listitem"><p>
Single object "nothrow" form, returning NULL on errors
</p></li><li class="listitem"><p>
Array <code class="function">new</code>, throwing
<code class="classname">bad_alloc</code> on errors
</p></li><li class="listitem"><p>
Array nothrow <code class="function">new</code>, returning
<code class="constant">NULL</code> on errors
</p></li><li class="listitem"><p>
Placement <code class="function">new</code>, which does nothing (like
it's supposed to)
</p></li><li class="listitem"><p>
Placement array <code class="function">new</code>, which also does
nothing
</p></li></ul></div><p>
They are distinguished by the parameters that you pass to them, like
any other overloaded function. The six flavors of <code class="function">delete</code>
In C++98 there are six flavors each of <code class="function">operator new</code>
and <code class="function">operator delete</code>, so make certain that you're
using the right ones.
Here are quickie descriptions of <code class="function">operator new</code>:
</p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="code">void* operator new(std::size_t);</code></span></dt><dd>
Single object form.
Throws <code class="classname">std::bad_alloc</code> on error.
This is what most people are used to using.
</dd><dt><span class="term"><code class="code">void* operator new(std::size_t, std::nothrow_t) noexcept;</code></span></dt><dd>
Single object <span class="quote">“<span class="quote">nothrow</span>”</span> form.
Calls <code class="code">operator new(std::size_t)</code> but if that throws,
returns a null pointer instead.
</dd><dt><span class="term"><code class="code">void* operator new[](std::size_t);</code></span></dt><dd>
Array <code class="function">new</code>.
Calls <code class="code">operator new(std::size_t)</code> and so
throws <code class="classname">std::bad_alloc</code> on error.
</dd><dt><span class="term"><code class="code">void* operator new[](std::size_t, std::nothrow_t) noexcept;</code></span></dt><dd>
Array <span class="quote">“<span class="quote">nothrow</span>”</span><code class="function">new</code>.
Calls <code class="code">operator new[](std::size_t)</code> but if that throws,
returns a null pointer instead.
</dd><dt><span class="term"><code class="code">void* operator new(std::size_t, void*) noexcept;</code></span></dt><dd>
Non-allocating, <span class="quote">“<span class="quote">placement</span>”</span> single-object <code class="function">new</code>,
which does nothing except return its argument.
This function cannot be replaced.
</dd><dt><span class="term"><code class="code">void* operator new[](std::size_t, void*) noexcept;</code></span></dt><dd>
Non-allocating, <span class="quote">“<span class="quote">placement</span>”</span> array <code class="function">new</code>,
which also does nothing except return its argument.
This function cannot be replaced.
</dd></dl></div><p>
They are distinguished by the arguments that you pass to them, like
any other overloaded function. The six flavors of
<code class="function">operator delete</code>
are distinguished the same way, but none of them are allowed to throw
an exception under any circumstances anyhow. (They match up for
completeness' sake.)
an exception under any circumstances anyhow. (The overloads match up
with the ones above, for completeness' sake.)
</p><p>
Remember that it is perfectly okay to call <code class="function">delete</code> on a
NULL pointer! Nothing happens, by definition. That is not the
same thing as deleting a pointer twice.
The C++ 2014 revision of the standard added two additional overloads of
<code class="function">operator delete</code> for <span class="quote">“<span class="quote">sized deallocation</span>”</span>,
allowing the compiler to provide the size of the storage being freed.
</p><p>
By default, if one of the <span class="quote">“<span class="quote">throwing <code class="function">new</code>s</span>”</span> can't
allocate the memory requested, it tosses an instance of a
<code class="classname">bad_alloc</code> exception (or, technically, some class derived
from it). You can change this by writing your own function (called a
new-handler) and then registering it with <code class="function">set_new_handler()</code>:
The C++ 2017 standard added even more overloads of both
<code class="function">operator new</code> and <code class="function">operator delete</code>
for allocating and deallocating storage for overaligned types.
These overloads correspond to each of the allocating forms of
<code class="function">operator new</code> and <code class="function">operator delete</code>
but with an additional parameter of type <span class="type">std::align_val_t</span>.
These new overloads are not interchangeable with the versions without
an aligment parameter, so if memory was allocated by an overload of
<code class="function">operator new</code> taking an alignment parameter,
then it must be decallocated by the corresponding overload of
<code class="function">operator delete</code> that takes an alignment parameter.
</p><p>
Apart from the non-allocating forms, the default versions of the array
and nothrow <code class="function">operator new</code> functions will all result
in a call to either <code class="function">operator new(std::size_t)</code> or
<code class="function">operator new(std::size_t, std::align_val_t)</code>,
and similarly the default versions of the array and nothrow
<code class="function">operator delete</code> functions will result in a call to
either <code class="function">operator delete(void*)</code> or
<code class="function">operator delete(void*, std::align_val_t)</code>
(or the sized versions of those).
</p><p>
Apart from the non-allocating forms, any of these functions can be
replaced by defining a function with the same signature in your program.
Replacement versions must preserve certain guarantees, such as memory
obtained from a nothrow <code class="function">operator new</code> being free-able
by the normal (non-nothrow) <code class="function">operator delete</code>,
and the sized and unsized forms of <code class="function">operator delete</code>
being interchangeable (because it's unspecified whether
the compiler calls the sized delete instead of the normal one).
The simplest way to meet the guarantees is to only replace the ordinary
<code class="function">operator new(size_t)</code> and
<code class="function">operator delete(void*)</code> and
<code class="function">operator delete(void*, std::size_t)</code>
functions, and the replaced versions will be used by all of
<code class="function">operator new(size_t, nothrow_t)</code>,
<code class="function">operator new[](size_t)</code> and
<code class="function">operator new[](size_t, nothrow_t)</code>
and the corresponding <code class="function">operator delete</code> functions.
To support types with extended alignment you may also need to replace
<code class="function">operator new(size_t, align_val_t)</code> and
<code class="function">operator delete(void*, align_val_t)</code>
<code class="function">operator delete(void*, size_t, align_val_t)</code>
(which will then be used by the nothrow and array forms for
extended alignments).
If you do need to replace other forms (e.g. to define the nothrow
<code class="function">operator new</code> to allocate memory directly, so it
works with exceptions disabled) then make sure the memory it allocates
can still be freed by the non-nothrow forms of
<code class="function">operator delete</code>.
</p><p>
If the default versions of <code class="function">operator new(std::size_t)</code>
and <code class="function">operator new(size_t, std::align_val_t)</code>
can't allocate the memory requested, they usually throw an exception
object of type <code class="classname">std::bad_alloc</code> (or some class
derived from that). However, the program can influence that behavior
by registering a <span class="quote">“<span class="quote">new-handler</span>”</span>, because what
<code class="function">operator new</code> actually does is something like:
</p><pre class="programlisting">
typedef void (*PFV)(void);
while (true)
{
if (void* p = /* try to allocate memory */)
return p;
else if (std::new_handler h = std::get_new_handler ())
h ();
else
throw bad_alloc{};
}
</pre><p>
This means you can influence what happens on allocation failure by
writing your own new-handler and then registering it with
<code class="function">std::set_new_handler</code>:
</p><pre class="programlisting">
typedef void (*PFV)();
static char* safety;
static PFV old_handler;
@ -49,6 +124,7 @@
void my_new_handler ()
{
delete[] safety;
safety = nullptr;
popup_window ("Dude, you are running low on heap memory. You"
" should, like, close some windows, or something."
" The next time you run out, we're gonna burn!");
@ -62,10 +138,15 @@
old_handler = set_new_handler (&amp;my_new_handler);
...
}
</pre><p>
<code class="classname">bad_alloc</code> is derived from the base <code class="classname">exception</code>
class defined in Sect1 19.
</p></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="support.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="support.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="termination.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 4. 
</pre><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="std.support.memory.notes"></a>Additional Notes</h3></div></div></div><p>
Remember that it is perfectly okay to <code class="function">delete</code> a
null pointer! Nothing happens, by definition. That is not the
same thing as deleting a pointer twice.
</p><p>
<code class="classname">std::bad_alloc</code> is derived from the base
<code class="classname">std::exception</code> class,
see <a class="xref" href="diagnostics.html#std.diagnostics.exceptions" title="Exceptions">Exceptions</a>.
</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="support.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="support.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="termination.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 4. 
Support
 </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Termination</td></tr></table></div></body></html>

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</a></span></dt><dd><dl><dt><span class="chapter"><a href="support.html">4.
Support
</a></span></dt><dd><dl><dt><span class="section"><a href="support.html#std.support.types">Types</a></span></dt><dd><dl><dt><span class="section"><a href="support.html#std.support.types.fundamental">Fundamental Types</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.numeric_limits">Numeric Properties</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.null">NULL</a></span></dt></dl></dd><dt><span class="section"><a href="dynamic_memory.html">Dynamic Memory</a></span></dt><dt><span class="section"><a href="termination.html">Termination</a></span></dt><dd><dl><dt><span class="section"><a href="termination.html#support.termination.handlers">Termination Handlers</a></span></dt><dt><span class="section"><a href="termination.html#support.termination.verbose">Verbose Terminate Handler</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="diagnostics.html">5.
</a></span></dt><dd><dl><dt><span class="section"><a href="support.html#std.support.types">Types</a></span></dt><dd><dl><dt><span class="section"><a href="support.html#std.support.types.fundamental">Fundamental Types</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.numeric_limits">Numeric Properties</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.null">NULL</a></span></dt></dl></dd><dt><span class="section"><a href="dynamic_memory.html">Dynamic Memory</a></span></dt><dd><dl><dt><span class="section"><a href="dynamic_memory.html#std.support.memory.notes">Additional Notes</a></span></dt></dl></dd><dt><span class="section"><a href="termination.html">Termination</a></span></dt><dd><dl><dt><span class="section"><a href="termination.html#support.termination.handlers">Termination Handlers</a></span></dt><dt><span class="section"><a href="termination.html#support.termination.verbose">Verbose Terminate Handler</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="diagnostics.html">5.
Diagnostics
</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions">Exceptions</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.api">API Reference</a></span></dt><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.data">Adding Data to <code class="classname">exception</code></a></span></dt></dl></dd><dt><span class="section"><a href="errno.html">Use of errno by the library</a></span></dt><dt><span class="section"><a href="concept_checking.html">Concept Checking</a></span></dt></dl></dd><dt><span class="chapter"><a href="utilities.html">6.

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</h1></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="chapter"><a href="support.html">4.
Support
</a></span></dt><dd><dl><dt><span class="section"><a href="support.html#std.support.types">Types</a></span></dt><dd><dl><dt><span class="section"><a href="support.html#std.support.types.fundamental">Fundamental Types</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.numeric_limits">Numeric Properties</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.null">NULL</a></span></dt></dl></dd><dt><span class="section"><a href="dynamic_memory.html">Dynamic Memory</a></span></dt><dt><span class="section"><a href="termination.html">Termination</a></span></dt><dd><dl><dt><span class="section"><a href="termination.html#support.termination.handlers">Termination Handlers</a></span></dt><dt><span class="section"><a href="termination.html#support.termination.verbose">Verbose Terminate Handler</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="diagnostics.html">5.
</a></span></dt><dd><dl><dt><span class="section"><a href="support.html#std.support.types">Types</a></span></dt><dd><dl><dt><span class="section"><a href="support.html#std.support.types.fundamental">Fundamental Types</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.numeric_limits">Numeric Properties</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.null">NULL</a></span></dt></dl></dd><dt><span class="section"><a href="dynamic_memory.html">Dynamic Memory</a></span></dt><dd><dl><dt><span class="section"><a href="dynamic_memory.html#std.support.memory.notes">Additional Notes</a></span></dt></dl></dd><dt><span class="section"><a href="termination.html">Termination</a></span></dt><dd><dl><dt><span class="section"><a href="termination.html#support.termination.handlers">Termination Handlers</a></span></dt><dt><span class="section"><a href="termination.html#support.termination.verbose">Verbose Terminate Handler</a></span></dt></dl></dd></dl></dd><dt><span class="chapter"><a href="diagnostics.html">5.
Diagnostics
</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions">Exceptions</a></span></dt><dd><dl><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.api">API Reference</a></span></dt><dt><span class="section"><a href="diagnostics.html#std.diagnostics.exceptions.data">Adding Data to <code class="classname">exception</code></a></span></dt></dl></dd><dt><span class="section"><a href="errno.html">Use of errno by the library</a></span></dt><dt><span class="section"><a href="concept_checking.html">Concept Checking</a></span></dt></dl></dd><dt><span class="chapter"><a href="utilities.html">6.

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</th><td width="20%" align="right"> <a accesskey="n" href="dynamic_memory.html">Next</a></td></tr></table><hr /></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a id="std.support"></a>Chapter 4. 
Support
<a id="id-1.3.4.2.1.1.1" class="indexterm"></a>
</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="section"><a href="support.html#std.support.types">Types</a></span></dt><dd><dl><dt><span class="section"><a href="support.html#std.support.types.fundamental">Fundamental Types</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.numeric_limits">Numeric Properties</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.null">NULL</a></span></dt></dl></dd><dt><span class="section"><a href="dynamic_memory.html">Dynamic Memory</a></span></dt><dt><span class="section"><a href="termination.html">Termination</a></span></dt><dd><dl><dt><span class="section"><a href="termination.html#support.termination.handlers">Termination Handlers</a></span></dt><dt><span class="section"><a href="termination.html#support.termination.verbose">Verbose Terminate Handler</a></span></dt></dl></dd></dl></div><p>
</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl class="toc"><dt><span class="section"><a href="support.html#std.support.types">Types</a></span></dt><dd><dl><dt><span class="section"><a href="support.html#std.support.types.fundamental">Fundamental Types</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.numeric_limits">Numeric Properties</a></span></dt><dt><span class="section"><a href="support.html#std.support.types.null">NULL</a></span></dt></dl></dd><dt><span class="section"><a href="dynamic_memory.html">Dynamic Memory</a></span></dt><dd><dl><dt><span class="section"><a href="dynamic_memory.html#std.support.memory.notes">Additional Notes</a></span></dt></dl></dd><dt><span class="section"><a href="termination.html">Termination</a></span></dt><dd><dl><dt><span class="section"><a href="termination.html#support.termination.handlers">Termination Handlers</a></span></dt><dt><span class="section"><a href="termination.html#support.termination.verbose">Verbose Terminate Handler</a></span></dt></dl></dd></dl></div><p>
This part deals with the functions called and objects created
automatically during the course of a program's existence.
</p><p>
@ -53,7 +53,7 @@
Specializing parts of the library on these types is prohibited:
instead, use a POD.
</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="std.support.types.numeric_limits"></a>Numeric Properties</h3></div></div></div><p>
The header <code class="filename">limits</code> defines
The header <code class="filename">&lt;limits&gt;</code> defines
traits classes to give access to various implementation
defined-aspects of the fundamental types. The traits classes --
fourteen in total -- are all specializations of the class template
@ -102,28 +102,36 @@
The only change that might affect people is the type of
<code class="constant">NULL</code>: while it is required to be a macro,
the definition of that macro is <span class="emphasis"><em>not</em></span> allowed
to be <code class="constant">(void*)0</code>, which is often used in C.
to be an expression with pointer type such as
<code class="constant">(void*)0</code>, which is often used in C.
</p><p>
For <span class="command"><strong>g++</strong></span>, <code class="constant">NULL</code> is
<code class="code">#define</code>'d to be
<code class="constant">__null</code>, a magic keyword extension of
<span class="command"><strong>g++</strong></span>.
<span class="command"><strong>g++</strong></span> that is slightly safer than a plain integer.
</p><p>
The biggest problem of #defining <code class="constant">NULL</code> to be
something like <span class="quote">“<span class="quote">0L</span>”</span> is that the compiler will view
that as a long integer before it views it as a pointer, so
overloading won't do what you expect. (This is why
<span class="command"><strong>g++</strong></span> has a magic extension, so that
<code class="constant">NULL</code> is always a pointer.)
</p><p>In his book <a class="link" href="http://www.aristeia.com/books.html" target="_top"><span class="emphasis"><em>Effective
C++</em></span></a>, Scott Meyers points out that the best way
to solve this problem is to not overload on pointer-vs-integer
types to begin with. He also offers a way to make your own magic
<code class="constant">NULL</code> that will match pointers before it
matches integers.
</p><p>See the
<a class="link" href="http://www.aristeia.com/books.html" target="_top"><span class="emphasis"><em>Effective
C++ CD</em></span></a> example.
overloading won't do what you expect. It might not even have the
same size as a pointer, so passing <code class="constant">NULL</code> to a
varargs function where a pointer is expected might not even work
correctly if <code class="code">sizeof(NULL) &lt; sizeof(void*)</code>.
The G++ <code class="constant">__null</code> extension is defined so that
<code class="code">sizeof(__null) == sizeof(void*)</code> to avoid this problem.
</p><p>
Scott Meyers explains this in more detail in his book
<a class="link" href="https://www.aristeia.com/books.html" target="_top"><span class="emphasis"><em>Effective
Modern C++</em></span></a> and as a guideline to solve this problem
recommends to not overload on pointer-vs-integer types to begin with.
</p><p>
The C++ 2011 standard added the <code class="constant">nullptr</code> keyword,
which is a null pointer constant of a special type,
<code class="classname">std::nullptr_t</code>. Values of this type can be
implicitly converted to <span class="emphasis"><em>any</em></span> pointer type,
and cannot convert to integer types or be deduced as an integer type.
Unless you need to be compatible with C++98/C++03 or C you should prefer
to use <code class="constant">nullptr</code> instead of <code class="constant">NULL</code>.
</p></div></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="std_contents.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="std_contents.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="dynamic_memory.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Part II. 
Standard Contents
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41
libstdc++-v3/doc/html/manual/termination.html
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@ -3,7 +3,9 @@
Support
</th><td width="20%" align="right"> <a accesskey="n" href="diagnostics.html">Next</a></td></tr></table><hr /></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="std.support.termination"></a>Termination</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="support.termination.handlers"></a>Termination Handlers</h3></div></div></div><p>
Not many changes here to <code class="filename">cstdlib</code>. You should note that the
Not many changes here to
<code class="filename">&lt;cstdlib&gt;</code>.
You should note that the
<code class="function">abort()</code> function does not call the
destructors of automatic nor static objects, so if you're
depending on those to do cleanup, it isn't going to happen.
@ -24,8 +26,8 @@
The previous two actions are <span class="quote">“<span class="quote">interleaved,</span>”</span> that is,
given this pseudocode:
</p><pre class="programlisting">
extern "C or C++" void f1 (void);
extern "C or C++" void f2 (void);
extern "C or C++" void f1 ();
extern "C or C++" void f2 ();
static Thing obj1;
atexit(f1);
@ -43,11 +45,20 @@
Note also that <code class="function">atexit()</code> is only required to store 32
functions, and the compiler/library might already be using some of
those slots. If you think you may run out, we recommend using
the <code class="function">xatexit</code>/<code class="function">xexit</code> combination from <code class="literal">libiberty</code>, which has no such limit.
the <code class="function">xatexit</code>/<code class="function">xexit</code> combination
from <code class="literal">libiberty</code>, which has no such limit.
</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="support.termination.verbose"></a>Verbose Terminate Handler</h3></div></div></div><p>
If you are having difficulty with uncaught exceptions and want a
little bit of help debugging the causes of the core dumps, you can
make use of a GNU extension, the verbose terminate handler.
</p><p>
The verbose terminate handler is only available for hosted environments
(see <a class="xref" href="configure.html" title="Configure">Configuring</a>) and will be used
by default unless the library is built with
<code class="option">--disable-libstdcxx-verbose</code>
or with exceptions disabled.
If you need to enable it explicitly you can do so by calling the
<code class="function">std::set_terminate</code> function.
</p><pre class="programlisting">
#include &lt;exception&gt;
@ -61,12 +72,13 @@ int main()
</pre><p>
The <code class="function">__verbose_terminate_handler</code> function
obtains the name of the current exception, attempts to demangle
it, and prints it to stderr. If the exception is derived from
<code class="classname">exception</code> then the output from
it, and prints it to <code class="literal">stderr</code>.
If the exception is derived from
<code class="classname">std::exception</code> then the output from
<code class="function">what()</code> will be included.
</p><p>
Any replacement termination function is required to kill the
program without returning; this one calls abort.
program without returning; this one calls <code class="function">std::abort</code>.
</p><p>
For example:
</p><pre class="programlisting">
@ -99,13 +111,14 @@ int main(int argc)
Aborted
</code>
</pre><p>
The 'Aborted' line comes from the call to
<code class="function">abort()</code>, of course.
The 'Aborted' line is printed by the shell after the process exits
by calling <code class="function">abort()</code>.
</p><p>
This is the default termination handler; nothing need be done to
As this is the default termination handler, nothing need be done to
use it. To go back to the previous <span class="quote">“<span class="quote">silent death</span>”</span>
method, simply include <code class="filename">exception</code> and
<code class="filename">cstdlib</code>, and call
method, simply include
<code class="filename">&lt;exception&gt;</code> and
<code class="filename">&lt;cstdlib&gt;</code>, and call
</p><pre class="programlisting">
std::set_terminate(std::abort);
</pre><p>
@ -113,8 +126,8 @@ int main(int argc)
<code class="function">abort</code> as the terminate handler.
</p><p>
Note: the verbose terminate handler will attempt to write to
stderr. If your application closes stderr or redirects it to an
inappropriate location,
<code class="literal">stderr</code>. If your application closes
<code class="literal">stderr</code> or redirects it to an inappropriate location,
<code class="function">__verbose_terminate_handler</code> will behave in
an unspecified manner.
</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="dynamic_memory.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="support.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="diagnostics.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Dynamic Memory </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 5. 

34
libstdc++-v3/doc/xml/manual/diagnostics.xml
View File

@ -21,28 +21,38 @@
<section xml:id="std.diagnostics.exceptions.api"><info><title>API Reference</title></info>
<para>
All exception objects are defined in one of the standard header
files: <filename>exception</filename>,
<filename>stdexcept</filename>, <filename>new</filename>, and
<filename>typeinfo</filename>.
Most exception classes are defined in one of the standard headers
<filename class="headerfile">&lt;exception&gt;</filename>,
<filename class="headerfile">&lt;stdexcept&gt;</filename>,
<filename class="headerfile">&lt;new&gt;</filename>, and
<filename class="headerfile">&lt;typeinfo&gt;</filename>.
The C++ 2011 revision of the standard added more exception types
in the headers
<filename class="headerfile">&lt;functional&gt;</filename>,
<filename class="headerfile">&lt;future&gt;</filename>,
<filename class="headerfile">&lt;regex&gt;</filename>, and
<filename class="headerfile">&lt;system_error&gt;</filename>.
The C++ 2017 revision of the standard added more exception types
in the headers
<filename class="headerfile">&lt;any&gt;</filename>,
<filename class="headerfile">&lt;filesystem&gt;</filename>,
<filename class="headerfile">&lt;optional&gt;</filename>, and
<filename class="headerfile">&lt;variant&gt;</filename>.
</para>
<para>
The base exception object is <classname>exception</classname>,
located in <filename>exception</filename>. This object has no
<classname>string</classname> member.
All exceptions thrown by the library have a base class of type
<classname>std::exception</classname>,
defined in <filename class="headerfile">&lt;exception&gt;</filename>.
This type has no <classname>std::string</classname> member.
</para>
<para>
Derived from this are several classes that may have a
<classname>string</classname> member: a full hierarchy can be
<classname>std::string</classname> member. A full hierarchy can be
found in the source documentation.
</para>
<para>
Full API details.
</para>
<!-- Doxygen XML: api/group__exceptions.xml -->
</section>

299
libstdc++-v3/doc/xml/manual/support.xml
View File

@ -26,9 +26,9 @@
<section xml:id="std.support.types" xreflabel="Types"><info><title>Types</title></info>
<?dbhtml filename="fundamental_types.html"?>
<section xml:id="std.support.types.fundamental" xreflabel="Fundamental Types"><info><title>Fundamental Types</title></info>
<para>
C++ has the following builtin types:
</para>
@ -90,11 +90,9 @@
</section>
<section xml:id="std.support.types.numeric_limits" xreflabel="Numeric Properties"><info><title>Numeric Properties</title></info>
<para>
The header <filename class="headerfile">limits</filename> defines
The header <filename class="headerfile">&lt;limits&gt;</filename> defines
traits classes to give access to various implementation
defined-aspects of the fundamental types. The traits classes --
fourteen in total -- are all specializations of the class template
@ -145,42 +143,50 @@
</section>
<section xml:id="std.support.types.null" xreflabel="NULL"><info><title>NULL</title></info>
<para>
The only change that might affect people is the type of
<constant>NULL</constant>: while it is required to be a macro,
the definition of that macro is <emphasis>not</emphasis> allowed
to be <constant>(void*)0</constant>, which is often used in C.
to be an expression with pointer type such as
<constant>(void*)0</constant>, which is often used in C.
</para>
<para>
For <command>g++</command>, <constant>NULL</constant> is
<code>#define</code>'d to be
<constant>__null</constant>, a magic keyword extension of
<command>g++</command>.
<command>g++</command> that is slightly safer than a plain integer.
</para>
<para>
The biggest problem of #defining <constant>NULL</constant> to be
something like <quote>0L</quote> is that the compiler will view
that as a long integer before it views it as a pointer, so
overloading won't do what you expect. (This is why
<command>g++</command> has a magic extension, so that
<constant>NULL</constant> is always a pointer.)
overloading won't do what you expect. It might not even have the
same size as a pointer, so passing <constant>NULL</constant> to a
varargs function where a pointer is expected might not even work
correctly if <code>sizeof(NULL) &lt; sizeof(void*)</code>.
The G++ <constant>__null</constant> extension is defined so that
<code>sizeof(__null) == sizeof(void*)</code> to avoid this problem.
</para>
<para>In his book <link xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="http://www.aristeia.com/books.html"><emphasis>Effective
C++</emphasis></link>, Scott Meyers points out that the best way
to solve this problem is to not overload on pointer-vs-integer
types to begin with. He also offers a way to make your own magic
<constant>NULL</constant> that will match pointers before it
matches integers.
<para>
Scott Meyers explains this in more detail in his book
<link xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="https://www.aristeia.com/books.html"><emphasis>Effective
Modern C++</emphasis></link> and as a guideline to solve this problem
recommends to not overload on pointer-vs-integer types to begin with.
</para>
<para>See the
<link xmlns:xlink="http://www.w3.org/1999/xlink"
xlink:href="http://www.aristeia.com/books.html"><emphasis>Effective
C++ CD</emphasis></link> example.
<para>
The C++ 2011 standard added the <constant>nullptr</constant> keyword,
which is a null pointer constant of a special type,
<classname>std::nullptr_t</classname>. Values of this type can be
implicitly converted to <emphasis>any</emphasis> pointer type,
and cannot convert to integer types or be deduced as an integer type.
Unless you need to be compatible with C++98/C++03 or C you should prefer
to use <constant>nullptr</constant> instead of <constant>NULL</constant>.
</para>
</section>
@ -188,59 +194,157 @@
<section xml:id="std.support.memory" xreflabel="Dynamic Memory"><info><title>Dynamic Memory</title></info>
<?dbhtml filename="dynamic_memory.html"?>
<para>
There are six flavors each of <function>new</function> and
<function>delete</function>, so make certain that you're using the right
ones. Here are quickie descriptions of <function>new</function>:
In C++98 there are six flavors each of <function>operator new</function>
and <function>operator delete</function>, so make certain that you're
using the right ones.
Here are quickie descriptions of <function>operator new</function>:
</para>
<itemizedlist>
<listitem><para>
single object form, throwing a
<classname>bad_alloc</classname> on errors; this is what most
people are used to using
</para></listitem>
<listitem><para>
Single object "nothrow" form, returning NULL on errors
</para></listitem>
<listitem><para>
Array <function>new</function>, throwing
<classname>bad_alloc</classname> on errors
</para></listitem>
<listitem><para>
Array nothrow <function>new</function>, returning
<constant>NULL</constant> on errors
</para></listitem>
<listitem><para>
Placement <function>new</function>, which does nothing (like
it's supposed to)
</para></listitem>
<listitem><para>
Placement array <function>new</function>, which also does
nothing
</para></listitem>
</itemizedlist>
<variablelist>
<varlistentry>
<term><code>void* operator new(std::size_t);</code></term>
<listitem>
Single object form.
Throws <classname>std::bad_alloc</classname> on error.
This is what most people are used to using.
</listitem>
</varlistentry>
<varlistentry>
<term><code>void* operator new(std::size_t, std::nothrow_t) noexcept;</code></term>
<listitem>
Single object <quote>nothrow</quote> form.
Calls <code>operator new(std::size_t)</code> but if that throws,
returns a null pointer instead.
</listitem>
</varlistentry>
<varlistentry>
<term><code>void* operator new[](std::size_t);</code></term>
<listitem>
Array <function>new</function>.
Calls <code>operator new(std::size_t)</code> and so
throws <classname>std::bad_alloc</classname> on error.
</listitem>
</varlistentry>
<varlistentry>
<term><code>void* operator new[](std::size_t, std::nothrow_t) noexcept;</code></term>
<listitem>
Array <quote>nothrow</quote> <function>new</function>.
Calls <code>operator new[](std::size_t)</code> but if that throws,
returns a null pointer instead.
</listitem>
</varlistentry>
<varlistentry>
<term><code>void* operator new(std::size_t, void*) noexcept;</code></term>
<listitem>
Non-allocating, <quote>placement</quote> single-object <function>new</function>,
which does nothing except return its argument.
This function cannot be replaced.
</listitem>
</varlistentry>
<varlistentry>
<term><code>void* operator new[](std::size_t, void*) noexcept;</code></term>
<listitem>
Non-allocating, <quote>placement</quote> array <function>new</function>,
which also does nothing except return its argument.
This function cannot be replaced.
</listitem>
</varlistentry>
</variablelist>
<para>
They are distinguished by the parameters that you pass to them, like
any other overloaded function. The six flavors of <function>delete</function>
They are distinguished by the arguments that you pass to them, like
any other overloaded function. The six flavors of
<function>operator delete</function>
are distinguished the same way, but none of them are allowed to throw
an exception under any circumstances anyhow. (They match up for
completeness' sake.)
an exception under any circumstances anyhow. (The overloads match up
with the ones above, for completeness' sake.)
</para>
<para>
Remember that it is perfectly okay to call <function>delete</function> on a
NULL pointer! Nothing happens, by definition. That is not the
same thing as deleting a pointer twice.
The C++ 2014 revision of the standard added two additional overloads of
<function>operator delete</function> for <quote>sized deallocation</quote>,
allowing the compiler to provide the size of the storage being freed.
</para>
<para>
By default, if one of the <quote>throwing <function>new</function>s</quote> can't
allocate the memory requested, it tosses an instance of a
<classname>bad_alloc</classname> exception (or, technically, some class derived
from it). You can change this by writing your own function (called a
new-handler) and then registering it with <function>set_new_handler()</function>:
The C++ 2017 standard added even more overloads of both
<function>operator new</function> and <function>operator delete</function>
for allocating and deallocating storage for overaligned types.
These overloads correspond to each of the allocating forms of
<function>operator new</function> and <function>operator delete</function>
but with an additional parameter of type <type>std::align_val_t</type>.
These new overloads are not interchangeable with the versions without
an aligment parameter, so if memory was allocated by an overload of
<function>operator new</function> taking an alignment parameter,
then it must be decallocated by the corresponding overload of
<function>operator delete</function> that takes an alignment parameter.
</para>
<para>
Apart from the non-allocating forms, the default versions of the array
and nothrow <function>operator new</function> functions will all result
in a call to either <function>operator new(std::size_t)</function> or
<function>operator new(std::size_t, std::align_val_t)</function>,
and similarly the default versions of the array and nothrow
<function>operator delete</function> functions will result in a call to
either <function>operator delete(void*)</function> or
<function>operator delete(void*, std::align_val_t)</function>
(or the sized versions of those).
</para>
<para>
Apart from the non-allocating forms, any of these functions can be
replaced by defining a function with the same signature in your program.
Replacement versions must preserve certain guarantees, such as memory
obtained from a nothrow <function>operator new</function> being free-able
by the normal (non-nothrow) <function>operator delete</function>,
and the sized and unsized forms of <function>operator delete</function>
being interchangeable (because it's unspecified whether
the compiler calls the sized delete instead of the normal one).
The simplest way to meet the guarantees is to only replace the ordinary
<function>operator new(size_t)</function> and
<function>operator delete(void*)</function> and
<function>operator delete(void*, std::size_t)</function>
functions, and the replaced versions will be used by all of
<function>operator new(size_t, nothrow_t)</function>,
<function>operator new[](size_t)</function> and
<function>operator new[](size_t, nothrow_t)</function>
and the corresponding <function>operator delete</function> functions.
To support types with extended alignment you may also need to replace
<function>operator new(size_t, align_val_t)</function> and
<function>operator delete(void*, align_val_t)</function>
<function>operator delete(void*, size_t, align_val_t)</function>
(which will then be used by the nothrow and array forms for
extended alignments).
If you do need to replace other forms (e.g. to define the nothrow
<function>operator new</function> to allocate memory directly, so it
works with exceptions disabled) then make sure the memory it allocates
can still be freed by the non-nothrow forms of
<function>operator delete</function>.
</para>
<para>
If the default versions of <function>operator new(std::size_t)</function>
and <function>operator new(size_t, std::align_val_t)</function>
can't allocate the memory requested, they usually throw an exception
object of type <classname>std::bad_alloc</classname> (or some class
derived from that). However, the program can influence that behavior
by registering a <quote>new-handler</quote>, because what
<function>operator new</function> actually does is something like:
</para>
<programlisting>
typedef void (*PFV)(void);
while (true)
{
if (void* p = /* try to allocate memory */)
return p;
else if (std::new_handler h = std::get_new_handler ())
h ();
else
throw bad_alloc{};
}
</programlisting>
<para>
This means you can influence what happens on allocation failure by
writing your own new-handler and then registering it with
<function>std::set_new_handler</function>:
</para>
<programlisting>
typedef void (*PFV)();
static char* safety;
static PFV old_handler;
@ -248,6 +352,7 @@
void my_new_handler ()
{
delete[] safety;
safety = nullptr;
popup_window ("Dude, you are running low on heap memory. You"
" should, like, close some windows, or something."
" The next time you run out, we're gonna burn!");
@ -262,19 +367,32 @@
...
}
</programlisting>
<section xml:id="std.support.memory.notes" xreflabel="Dynamic Memory Notes"><info><title>Additional Notes</title></info>
<para>
<classname>bad_alloc</classname> is derived from the base <classname>exception</classname>
class defined in Sect1 19.
Remember that it is perfectly okay to <function>delete</function> a
null pointer! Nothing happens, by definition. That is not the
same thing as deleting a pointer twice.
</para>
<para>
<classname>std::bad_alloc</classname> is derived from the base
<classname>std::exception</classname> class,
see <xref linkend="std.diagnostics.exceptions"/>.
</para>
</section>
</section>
<section xml:id="std.support.termination" xreflabel="Termination"><info><title>Termination</title></info>
<?dbhtml filename="termination.html"?>
<section xml:id="support.termination.handlers" xreflabel="Termination Handlers"><info><title>Termination Handlers</title></info>
<para>
Not many changes here to <filename class="headerfile">cstdlib</filename>. You should note that the
Not many changes here to
<filename class="headerfile">&lt;cstdlib&gt;</filename>.
You should note that the
<function>abort()</function> function does not call the
destructors of automatic nor static objects, so if you're
depending on those to do cleanup, it isn't going to happen.
@ -306,8 +424,8 @@
given this pseudocode:
</para>
<programlisting>
extern "C or C++" void f1 (void);
extern "C or C++" void f2 (void);
extern "C or C++" void f1 ();
extern "C or C++" void f2 ();
static Thing obj1;
atexit(f1);
@ -329,19 +447,30 @@
Note also that <function>atexit()</function> is only required to store 32
functions, and the compiler/library might already be using some of
those slots. If you think you may run out, we recommend using
the <function>xatexit</function>/<function>xexit</function> combination from <literal>libiberty</literal>, which has no such limit.
the <function>xatexit</function>/<function>xexit</function> combination
from <literal>libiberty</literal>, which has no such limit.
</para>
</section>
<section xml:id="support.termination.verbose" xreflabel="Verbose Terminate Handler"><info><title>Verbose Terminate Handler</title></info>
<?dbhtml filename="verbose_termination.html"?>
<para>
If you are having difficulty with uncaught exceptions and want a
little bit of help debugging the causes of the core dumps, you can
make use of a GNU extension, the verbose terminate handler.
</para>
<para>
The verbose terminate handler is only available for hosted environments
(see <xref linkend="manual.intro.setup.configure"/>) and will be used
by default unless the library is built with
<option>--disable-libstdcxx-verbose</option>
or with exceptions disabled.
If you need to enable it explicitly you can do so by calling the
<function>std::set_terminate</function> function.
</para>
<programlisting>
#include &lt;exception&gt;
@ -357,14 +486,15 @@ int main()
<para>
The <function>__verbose_terminate_handler</function> function
obtains the name of the current exception, attempts to demangle
it, and prints it to stderr. If the exception is derived from
<classname>exception</classname> then the output from
it, and prints it to <literal>stderr</literal>.
If the exception is derived from
<classname>std::exception</classname> then the output from
<function>what()</function> will be included.
</para>
<para>
Any replacement termination function is required to kill the
program without returning; this one calls abort.
program without returning; this one calls <function>std::abort</function>.
</para>
<para>
@ -407,15 +537,16 @@ int main(int argc)
</screen>
<para>
The 'Aborted' line comes from the call to
<function>abort()</function>, of course.
The 'Aborted' line is printed by the shell after the process exits
by calling <function>abort()</function>.
</para>
<para>
This is the default termination handler; nothing need be done to
As this is the default termination handler, nothing need be done to
use it. To go back to the previous <quote>silent death</quote>
method, simply include <filename>exception</filename> and
<filename>cstdlib</filename>, and call
method, simply include
<filename class="headerfile">&lt;exception&gt;</filename> and
<filename class="headerfile">&lt;cstdlib&gt;</filename>, and call
</para>
<programlisting>
@ -429,8 +560,8 @@ int main(int argc)
<para>
Note: the verbose terminate handler will attempt to write to
stderr. If your application closes stderr or redirects it to an
inappropriate location,
<literal>stderr</literal>. If your application closes
<literal>stderr</literal> or redirects it to an inappropriate location,
<function>__verbose_terminate_handler</function> will behave in
an unspecified manner.
</para>