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1 files changed, 112 insertions, 90 deletions
diff --git a/docs/programmer_reference/stl_primitive_rw.html b/docs/programmer_reference/stl_primitive_rw.html index a17d1d3f..be44c1be 100644 --- a/docs/programmer_reference/stl_primitive_rw.html +++ b/docs/programmer_reference/stl_primitive_rw.html @@ -14,7 +14,7 @@ <body> <div xmlns="" class="navheader"> <div class="libver"> - <p>Library Version 11.2.5.3</p> + <p>Library Version 12.1.6.1</p> </div> <table width="100%" summary="Navigation header"> <tr> @@ -40,126 +40,146 @@ <dl> <dt> <span class="sect2"> - <a href="stl_primitive_rw.html#idp1288424">Storing strings</a> + <a href="stl_primitive_rw.html#idp849056">Storing strings</a> </span> </dt> </dl> </div> - <p> - To store simple primitive types such as <code class="literal">int</code>, - <code class="literal">long</code>, <code class="literal">double</code>, and so forth, an - additional type parameter for the container class - templates is needed. For example, to store an <code class="literal">int</code> - in a <code class="classname">db_vector</code>, use this container class: -</p> + <p> + To store simple primitive types such as + <code class="literal">int</code>, <code class="literal">long</code>, + <code class="literal">double</code>, and so forth, an additional + type parameter for the container class templates is needed. + For example, to store an <code class="literal">int</code> in a + <code class="classname">db_vector</code>, use this container + class: + </p> <pre class="programlisting">db_vector<int, ElementHolder<int> >;</pre> - <p> - To map integers to doubles, use this: -</p> + <p> + To map integers to doubles, use this: + </p> <pre class="programlisting">db_map<int, double, ElementHolder<double> >;</pre> - <p> - To store a <code class="literal">char*</code> string with <code class="literal">long</code> keys, - use this: -</p> + <p> + To store a <code class="literal">char*</code> string with + <code class="literal">long</code> keys, use this: + </p> <pre class="programlisting">db_map<long, char*, ElementHolder<char*> >;</pre> - <p> - Use this for <code class="literal">const char*</code> strings: -</p> + <p> + Use this for <code class="literal">const char*</code> strings: + </p> <pre class="programlisting">db_map<long, const char*, ElementHolder<const char*> >;</pre> - <p> - To map one const string to another, use this type: -</p> + <p> + To map one const string to another, use this type: + </p> <pre class="programlisting">db_map<const char*, const char*, ElementHolder<const char*> >;</pre> - <p> - The <code class="methodname">StlAdvancedFeaturesExample::primitive()</code> method demonstrates more of these examples. -</p> + <p> + The + <code class="methodname">StlAdvancedFeaturesExample::primitive()</code> + method demonstrates more of these examples. + </p> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> - <h3 class="title"><a id="idp1288424"></a>Storing strings</h3> + <h3 class="title"><a id="idp849056"></a>Storing strings</h3> </div> </div> </div> <p> - For <code class="literal">char*</code> and <code class="literal">wchar_t*</code> strings, - <code class="methodname">_DB_STL_StoreElement()</code> must be called - following partial or total modifications before iterator movement, - <code class="literal">container::operator[]</code> or - <code class="literal">iterator::operator*/-></code> calls. Without the - <code class="methodname">_DB_STL_StoreElement()</code> call, the modified - change will be lost. If storing an new value like this: -</p> + For <code class="literal">char*</code> and + <code class="literal">wchar_t*</code> strings, + <code class="methodname">_DB_STL_StoreElement()</code> must + be called following partial or total modifications before + iterator movement, + <code class="literal">container::operator[]</code> or + <code class="literal">iterator::operator*/-></code> calls. + Without the + <code class="methodname">_DB_STL_StoreElement()</code> call, + the modified change will be lost. If storing an new value + like this: + </p> <pre class="programlisting">*iterator = new_char_star_string;</pre> <p> - the call to <code class="methodname">_DB_STL_StoreElement()</code> is not needed. -</p> - <p> - Note that passing a NULL pointer to a container of - <code class="literal">char*</code> type or passing a - <code class="classname">std::string</code> with no contents at all will insert - an empty string of zero length into the database. -</p> - <p> - The string returned from a container will not live beyond the next - iterator movement call, <code class="literal">container::operator[]</code> or - <code class="literal">iterator::operator*/-></code> call. -</p> + the call to + <code class="methodname">_DB_STL_StoreElement()</code> is not + needed. + </p> + <p> + Note that passing a NULL pointer to a container of + <code class="literal">char*</code> type or passing a + <code class="classname">std::string</code> with no contents at + all will insert an empty string of zero length into the + database. + </p> + <p> + The string returned from a container will not live + beyond the next iterator movement call, + <code class="literal">container::operator[]</code> or + <code class="literal">iterator::operator*/-></code> call. + </p> <p> - - A <span class="bold"><strong>db_map::value_type::second_type</strong></span> or - <span class="bold"><strong>db_map::datatype_wrap</strong></span> should be used - to hold a reference to a <code class="literal">container::operator[]</code> - return value. Then the reference should be used for repeated - references to that value. The *iterator is of type - <code class="literal">ElementHolder<char *></code>, which can be automatically converted to a - <code class="literal">char *</code> pointer using its type conversion operator. - Wherever an auto conversion is done by the compiler, the conversion - operator of <code class="literal">ElementHolder<T></code> is called. This - avoids almost all explicit conversions, except for two use cases: - -</p> + A <span class="bold"><strong>db_map::value_type::second_type</strong></span> or + <span class="bold"><strong>db_map::datatype_wrap</strong></span> + should be used to hold a reference to a + <code class="literal">container::operator[]</code> return value. + Then the reference should be used for repeated references + to that value. The *iterator is of type + <code class="literal">ElementHolder<char *></code>, which + can be automatically converted to a <code class="literal">char*</code> pointer + using its type conversion + operator. Wherever an auto conversion is done by the + compiler, the conversion operator of + <code class="literal">ElementHolder<T></code> is called. + This avoids almost all explicit conversions, except for + two use cases: + </p> <div class="orderedlist"> <ol type="1"> <li> - <p> - The *iterator is used as a "..." parameter like this: - </p> + <p> + The *iterator is used as a "..." parameter like + this: + </p> <pre class="programlisting">printf("this is the special case %s", *iterator);</pre> - <p> - This compiles but causes errors. Instead, an explicit cast - should be used: - </p> + <p> + This compiles but causes errors. Instead, an + explicit cast should be used: + </p> <pre class="programlisting">printf("this is the special case %s", (char *)*iterator);</pre> </li> <li> <p> - For some old compilers, such as gcc3.4.6, the *iterator cannot be - used with the ternary <code class="literal">?</code> operator, like - this: - </p> + For some old compilers, such as gcc3.4.6, the + *iterator cannot be used with the ternary + <code class="literal">?</code> operator, like this: + </p> <pre class="programlisting">expr ? *iterator : var</pre> - <p> - Even when <span class="bold"><strong>var</strong></span> is the same - type as the iterator's <code class="literal">value_type</code>, the - compiler fails to perform an auto conversion. - </p> + <p> + Even when <span class="bold"><strong>var</strong></span> + is the same type as the iterator's + <code class="literal">value_type</code>, the compiler + fails to perform an auto conversion. + </p> </li> </ol> </div> <p> - When using <code class="classname">std::string</code> or - <code class="classname">std::wstring</code> as the data type for dbstl - containers — that is, <code class="classname">db_vector<string></code>, - and <code class="classname">db_map<string, wstring></code> — the - string's content rather than the string object itself is stored in order - to maintain persistence. -</p> - <p> - You can find example code demonstrating string storage in the - <code class="methodname">StlAdvancedFeaturesExample::char_star_string_storage()</code> and - <code class="methodname">StlAdvancedFeaturesExample::storing_std_strings()</code> methods. -</p> + When using <code class="classname">std::string</code> or + <code class="classname">std::wstring</code> as the data type + for dbstl containers — that is, + <code class="classname">db_vector<string></code>, and + <code class="classname">db_map<string, wstring></code> + — the string's content rather than the string object + itself is stored in order to maintain persistence. + </p> + <p> + You can find example code demonstrating string storage + in the + <code class="methodname">StlAdvancedFeaturesExample::char_star_string_storage()</code> + and + <code class="methodname">StlAdvancedFeaturesExample::storing_std_strings()</code> + methods. + </p> </div> </div> <div class="navfooter"> @@ -173,11 +193,13 @@ <td width="40%" align="right"> <a accesskey="n" href="stl_complex_rw.html">Next</a></td> </tr> <tr> - <td width="40%" align="left" valign="top">Using dbstl in multithreaded applications </td> + <td width="40%" align="left" valign="top">Using dbstl in multithreaded + applications </td> <td width="20%" align="center"> <a accesskey="h" href="index.html">Home</a> </td> - <td width="40%" align="right" valign="top"> Store and Retrieve data or objects of complex types </td> + <td width="40%" align="right" valign="top"> Store and Retrieve data or + objects of complex types </td> </tr> </table> </div> |