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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libstdc++-v3/doc/xml/manual/diagnostics.xml | |
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Diffstat (limited to 'libstdc++-v3/doc/xml/manual/diagnostics.xml')
-rw-r--r-- | libstdc++-v3/doc/xml/manual/diagnostics.xml | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/libstdc++-v3/doc/xml/manual/diagnostics.xml b/libstdc++-v3/doc/xml/manual/diagnostics.xml new file mode 100644 index 000000000..1a6a3f17d --- /dev/null +++ b/libstdc++-v3/doc/xml/manual/diagnostics.xml @@ -0,0 +1,129 @@ +<chapter xmlns="http://docbook.org/ns/docbook" version="5.0" + xml:id="std.diagnostics" xreflabel="Diagnostics"> +<?dbhtml filename="diagnostics.html"?> + +<info><title> + Diagnostics + <indexterm><primary>Diagnostics</primary></indexterm> +</title> + <keywordset> + <keyword> + ISO C++ + </keyword> + <keyword> + library + </keyword> + </keywordset> +</info> + + + +<section xml:id="std.diagnostics.exceptions" xreflabel="Exceptions"><info><title>Exceptions</title></info> + <?dbhtml filename="exceptions.html"?> + + + <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>. + </para> + + <para> + The base exception object is <classname>exception</classname>, + located in <filename>exception</filename>. This object has no + <classname>string</classname> member. + </para> + + <para> + Derived from this are several classes that may have a + <classname>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> + <section xml:id="std.diagnostics.exceptions.data" xreflabel="Adding Data to Exceptions"><info><title>Adding Data to <classname>exception</classname></title></info> + + <para> + The standard exception classes carry with them a single string as + data (usually describing what went wrong or where the 'throw' took + place). It's good to remember that you can add your own data to + these exceptions when extending the hierarchy: + </para> + <programlisting> + struct My_Exception : public std::runtime_error + { + public: + My_Exception (const string& whatarg) + : std::runtime_error(whatarg), e(errno), id(GetDataBaseID()) { } + int errno_at_time_of_throw() const { return e; } + DBID id_of_thing_that_threw() const { return id; } + protected: + int e; + DBID id; // some user-defined type + }; + </programlisting> + + </section> +</section> + +<section xml:id="std.diagnostics.concept_checking" xreflabel="Concept Checking"><info><title>Concept Checking</title></info> + + <para> + In 1999, SGI added <quote>concept checkers</quote> to their + implementation of the STL: code which checked the template + parameters of instantiated pieces of the STL, in order to insure + that the parameters being used met the requirements of the + standard. For example, the Standard requires that types passed as + template parameters to <classname>vector</classname> be + "Assignable" (which means what you think it means). The + checking was done during compilation, and none of the code was + executed at runtime. + </para> + <para> + Unfortunately, the size of the compiler files grew significantly + as a result. The checking code itself was cumbersome. And bugs + were found in it on more than one occasion. + </para> + <para> + The primary author of the checking code, Jeremy Siek, had already + started work on a replacement implementation. The new code was + formally reviewed and accepted into + <link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="http://www.boost.org/libs/concept_check/concept_check.htm">the + Boost libraries</link>, and we are pleased to incorporate it into the + GNU C++ library. + </para> + <para> + The new version imposes a much smaller space overhead on the generated + object file. The checks are also cleaner and easier to read and + understand. + </para> + + <para> + They are off by default for all versions of GCC. + They can be enabled at configure time with + <link linkend="manual.intro.setup.configure"><literal>--enable-concept-checks</literal></link>. + You can enable them on a per-translation-unit basis with + <literal>-D_GLIBCXX_CONCEPT_CHECKS</literal>. + </para> + + <para> + Please note that the checks are based on the requirements in the original + C++ standard, some of which have changed in the upcoming C++0x revision. + Additionally, some correct code might be rejected by the concept checks, + for example template argument types may need to be complete when used in + a template definition, rather than at the point of instantiation. + There are no plans to address these shortcomings. + </para> + +</section> + +</chapter> |