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| author | Lorry Tar Creator <lorry-tar-importer@baserock.org> | 2015-02-17 17:25:57 +0000 |
|---|---|---|
| committer | <> | 2015-03-17 16:26:24 +0000 |
| commit | 780b92ada9afcf1d58085a83a0b9e6bc982203d1 (patch) | |
| tree | 598f8b9fa431b228d29897e798de4ac0c1d3d970 /docs/programmer_reference/stl_complex_rw.html | |
| parent | 7a2660ba9cc2dc03a69ddfcfd95369395cc87444 (diff) | |
| download | berkeleydb-master.tar.gz | |
Diffstat (limited to 'docs/programmer_reference/stl_complex_rw.html')
| -rw-r--r-- | docs/programmer_reference/stl_complex_rw.html | 533 |
1 files changed, 320 insertions, 213 deletions
diff --git a/docs/programmer_reference/stl_complex_rw.html b/docs/programmer_reference/stl_complex_rw.html index d173b63f..353bbbdd 100644 --- a/docs/programmer_reference/stl_complex_rw.html +++ b/docs/programmer_reference/stl_complex_rw.html @@ -14,11 +14,12 @@ <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> - <th colspan="3" align="center">Store and Retrieve data or objects of complex types </th> + <th colspan="3" align="center">Store and Retrieve data or + objects of complex types </th> </tr> <tr> <td width="20%" align="left"><a accesskey="p" href="stl_primitive_rw.html">Prev</a> </td> @@ -32,7 +33,8 @@ <div class="titlepage"> <div> <div> - <h2 class="title" style="clear: both"><a id="stl_complex_rw"></a>Store and Retrieve data or objects of complex types </h2> + <h2 class="title" style="clear: both"><a id="stl_complex_rw"></a>Store and Retrieve data or + objects of complex types </h2> </div> </div> </div> @@ -40,17 +42,17 @@ <dl> <dt> <span class="sect2"> - <a href="stl_complex_rw.html#idp1279008">Storing varying length objects</a> + <a href="stl_complex_rw.html#idp808056">Storing varying length objects</a> </span> </dt> <dt> <span class="sect2"> - <a href="stl_complex_rw.html#idp1278616">Storing arbitrary sequences</a> + <a href="stl_complex_rw.html#idp859120">Storing arbitrary sequences</a> </span> </dt> <dt> <span class="sect2"> - <a href="stl_complex_rw.html#idp1344912">Notes</a> + <a href="stl_complex_rw.html#idp909008">Notes</a> </span> </dt> </dl> @@ -59,46 +61,51 @@ <div class="titlepage"> <div> <div> - <h3 class="title"><a id="idp1279008"></a>Storing varying length objects</h3> + <h3 class="title"><a id="idp808056"></a>Storing varying length objects</h3> </div> </div> </div> <p> - A structure like this: -</p> + A structure like this: + </p> <pre class="programlisting">class SMSMsg { public: - size_t mysize; - time_t when; - size_t szmsg; - int to; - char msg[1]; + size_t mysize; + time_t when; + size_t szmsg; + int to; + char msg[1]; }; </pre> <p> - with a varying length string in <code class="literal">msg</code> cannot simply be - stored in a <code class="literal">db_vector<SMSMsg></code> without some - configuration on your part. This is because, by default, dbstl uses the - <span class="bold"><strong>sizeof()</strong></span> operator to get the size of - an object and then <code class="function">memcpy()</code> to copy the object. This - process is not suitable for this use-case as it will fail to capture the - variable length string contained in <code class="literal">msg</code>. -</p> - <p> - There are currently two ways to store these kind of objects: -</p> + with a varying length string in <code class="literal">msg</code> + cannot simply be stored in a + <code class="literal">db_vector<SMSMsg></code> without + some configuration on your part. This is because, by + default, dbstl uses the <span class="bold"><strong>sizeof()</strong></span> operator + to get the size of an object and then <code class="function">memcpy()</code> to copy the + object. This process is not suitable for this use-case as + it will fail to capture the variable length string + contained in <code class="literal">msg</code>. + </p> + <p> + There are currently two ways to store these kind of + objects: + </p> <div class="orderedlist"> <ol type="1"> <li> <p> - Register callback functions with dbstl that are used to measure an object's size, - and then marshal/unmarshal the object. - </p> + Register callback functions with dbstl that are + used to measure an object's size, and then + marshal/unmarshal the object. + </p> </li> <li> <p> - Use a <code class="classname">DbstlDbt</code> wrapper object. - </p> + Use a <code class="classname">DbstlDbt</code> wrapper + object. + </p> </li> </ol> </div> @@ -106,280 +113,380 @@ public: <div class="titlepage"> <div> <div> - <h4 class="title"><a id="idp1264432"></a>Storing by marshaling objects</h4> + <h4 class="title"><a id="idp838336"></a>Storing by marshaling objects</h4> </div> </div> </div> - <p> - One way to store an object that contains variable-sized fields is - to marshall all of the object's data into a single contiguous area - in memory, and then store the contents of that buffer. This means that upon retrieval, the - contents of the buffer must be unmarshalled. To do these things, - you must register three callback functions: - </p> + <p> + One way to store an object that contains + variable-sized fields is to marshall all of the + object's data into a single contiguous area in memory, + and then store the contents of that buffer. This means + that upon retrieval, the contents of the buffer must + be unmarshalled. To do these things, you must register + three callback functions: + </p> <div class="itemizedlist"> <ul type="disc"> <li> <p> - <code class="function">typedef void (*ElemRstoreFunct)(T& dest, const void *srcdata);</code> - </p> + <code class="function">typedef void + (*ElemRstoreFunct)(T& dest, const void + *srcdata);</code> + </p> <p> - This callback is used to unmarshal an object, updating <span class="bold"><strong>dest</strong></span> - using data found in <span class="bold"><strong>srcdata</strong></span>. The data in - <span class="bold"><strong>srcdata </strong></span> contains the chunk of memory into which the - object was originally marshalled. The default unmarshalling function simply performs a cast - (for example, <code class="literal">dest = *((T*)srcdata)</code>), which assumes the - <span class="bold"><strong>srcdata</strong></span> simply points to the memory layout of the object. - </p> + This callback is used to unmarshal an + object, updating <span class="bold"><strong>dest</strong></span> using + data found in <span class="bold"><strong>srcdata</strong></span>. + The data in <span class="bold"><strong>srcdata + </strong></span> contains the chunk of memory into + which the object was originally marshalled. + The default unmarshalling function simply + performs a cast (for example, <code class="literal">dest = + *((T*)srcdata)</code>), which assumes + the <span class="bold"><strong>srcdata</strong></span> + simply points to the memory layout of the + object. + </p> </li> <li> <p> - <code class="function">typedef size_t (*ElemSizeFunct)(const T& elem);</code> - </p> - <p> - This callback returns the size in bytes needed to store the - <span class="bold"><strong>elem</strong></span> object. By default this function - simply uses <span class="bold"><strong>sizeof(elem)</strong></span> to determine - the size of <span class="bold"><strong>elem</strong></span>. - </p> + <code class="function">typedef size_t + (*ElemSizeFunct)(const T& + elem);</code> + </p> + <p> + This callback returns the size in bytes + needed to store the <span class="bold"><strong>elem</strong></span> object. + By default this function simply uses <span class="bold"><strong>sizeof(elem)</strong></span> + to determine the size of <span class="bold"><strong>elem</strong></span>. + </p> </li> <li> <p> - <code class="function">typedef void (*ElemCopyFunct)(void *dest, const T&elem);</code> - </p> - <p> - This callback is used to arrange all data contained by <span class="bold"><strong>elem</strong></span> - into the chunk of memory to which <span class="bold"><strong>dest</strong></span> refers. The size of - <span class="bold"><strong>dest</strong></span> is set by the <code class="function">ElemSizeFunct</code> - function, discussed above. The default marshalling function simply uses - <code class="function">memcpy()</code> to copy <span class="bold"><strong>elem</strong></span> to - <span class="bold"><strong>dest</strong></span>. - </p> + <code class="function">typedef void (*ElemCopyFunct)(void + *dest, const T&elem);</code> + </p> + <p> + This callback is used to arrange all data + contained by <span class="bold"><strong>elem</strong></span> into + the chunk of memory to which <span class="bold"><strong>dest</strong></span> + refers. The size of <span class="bold"><strong>dest</strong></span> is set + by the <code class="function">ElemSizeFunct</code> + function, discussed above. The default + marshalling function simply uses + <code class="function">memcpy()</code> to copy + <span class="bold"><strong>elem</strong></span> to + <span class="bold"><strong>dest</strong></span>. + </p> </li> </ul> </div> - <p> - The <code class="function">DbstlElemTraits<SMSMsg>::instance()->set_size_function()</code>, - <code class="function">set_copy_function()</code> and <code class="function">set_restore_function()</code> methods - are used to register these callback functions. If a callback is not registered, its - default function is used. -</p> - <p> - By providing non-default implementations of the callbacks described here, you can store objects - of varying length and/or objects which do not reside in a continuous memory chunk — for - example, objects containing a pointer which refers another object, or a string, and so forth. - As a result, containers/iterators can manage variable length objects in the same as they would - manage objects that reside in continuous chunks of memory and are of identical size. -</p> + <p> + The + <code class="function">DbstlElemTraits<SMSMsg>::instance()->set_size_function()</code>, + <code class="function">set_copy_function()</code> and + <code class="function">set_restore_function()</code> + methods are used to register these callback functions. + If a callback is not registered, its default function + is used. + </p> + <p> + By providing non-default implementations of the + callbacks described here, you can store objects of + varying length and/or objects which do not reside in a + continuous memory chunk — for example, objects + containing a pointer which refers another object, or a + string, and so forth. As a result, + containers/iterators can manage variable length + objects in the same as they would manage objects that + reside in continuous chunks of memory and are of + identical size. + </p> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> - <h4 class="title"><a id="idp1266088"></a>Using a <code class="classname">DbstlDbt</code> wrapper object</h4> + <h4 class="title"><a id="idp880480"></a>Using a <code class="classname">DbstlDbt</code> wrapper + object</h4> </div> </div> </div> <p> - To use a <code class="classname">DbstlDbt</code> wrapper object to store objects of variable length, a - <code class="literal">db_vector<DbstlDbt></code> container is used to store complex objects in a - <code class="classname">db_vector</code>. <code class="classname">DbstlDbt</code> derives from DB C++ API's - <code class="classname">Dbt</code>class, but can manage its referenced memory properly and release it - upon destruction. The memory referenced by <code class="classname">DbstlDbt</code> objects is required - to be allocated using the <code class="function">malloc()</code>/<code class="function">realloc()</code> functions - from the standard C library. -</p> - <p> - Note that the use of <code class="classname">DbstlDbt</code> wrapper class is not ideal. It exists only - to allow raw bytes of no specific type to be stored in a container. -</p> - <p> - To store an <code class="classname">SMSMsg</code> object into a <code class="literal">db_vector<DbstlDbt></code> - container using a <code class="classname">DbstlDbt</code> object: -</p> + To use a <code class="classname">DbstlDbt</code> wrapper + object to store objects of variable length, a + <code class="literal">db_vector<DbstlDbt></code> + container is used to store complex objects in a + <code class="classname">db_vector</code>. + <code class="classname">DbstlDbt</code> derives from DB + C++ API's <code class="classname">Dbt</code>class, but can + manage its referenced memory properly and release it + upon destruction. The memory referenced by + <code class="classname">DbstlDbt</code> objects is + required to be allocated using the + <code class="function">malloc()</code>/<code class="function">realloc()</code> + functions from the standard C library. + </p> + <p> + Note that the use of + <code class="classname">DbstlDbt</code> wrapper class is + not ideal. It exists only to allow raw bytes of no + specific type to be stored in a container. + </p> + <p> + To store an <code class="classname">SMSMsg</code> object + into a <code class="literal">db_vector<DbstlDbt></code> + container using a <code class="classname">DbstlDbt</code> + object: + </p> <div class="orderedlist"> <ol type="1"> - <li> - Wrap the <code class="classname">SMSMSg</code> object into a <code class="classname">DbstlDbt</code> object, - then marshal the SMSMsg object properly into the memory chunk referenced by - <code class="methodname">DbstlDbt::data</code>. -</li> - <li> - Store the <code class="classname">DbstlDbt</code> object into a <code class="literal">db_vector<DbstlDbt></code> - container. The bytes in the memory chunk referenced by the <code class="classname">DbstlDbt</code> object's - <span class="bold"><strong>data</strong></span> member are stored in the - <code class="literal">db_vector<DbstlDbt></code> container. -</li> - <li> - Reading from the container returns a <code class="classname">DbstlDbt</code> object whose - <span class="bold"><strong>data</strong></span> field points to the <code class="classname">SMSMsg</code> object - located in a continuous chunk of memory. The application needs to perform its own unmarshalling. -</li> - <li> - The memory referenced by <code class="literal">DbstlDbt::data</code> is freed automatically, - and so the application should not attempt to free the memory. -</li> + <li> + Wrap the <code class="classname">SMSMSg</code> + object into a <code class="classname">DbstlDbt</code> + object, then marshal the SMSMsg object properly + into the memory chunk referenced by + <code class="methodname">DbstlDbt::data</code>. + </li> + <li> + Store the <code class="classname">DbstlDbt</code> + object into a + <code class="literal">db_vector<DbstlDbt></code> + container. The bytes in the memory chunk + referenced by the <code class="classname">DbstlDbt</code> + object's <span class="bold"><strong>data</strong></span> + member are stored in the + <code class="literal">db_vector<DbstlDbt></code> + container. + </li> + <li> + Reading from the container returns a + <code class="classname">DbstlDbt</code> object whose + <span class="bold"><strong>data</strong></span> field + points to the <code class="classname">SMSMsg</code> object + located in a continuous chunk of memory. The + application needs to perform its own + unmarshalling. + </li> + <li> + The memory referenced by + <code class="literal">DbstlDbt::data</code> is freed + automatically, and so the application should not + attempt to free the memory. + </li> </ol> </div> <p> - <code class="classname">ElementHolder</code> should not be used to store objects of a class because it - doesn't support access to object members using <span class="bold"><strong>(*iter).member</strong></span> - or <span class="bold"><strong>iter->member</strong></span> expressions. In this case, the default - <code class="literal">ElementRef<ddt></code> is used automatically. -</p> - <p> - <code class="classname">ElementRef</code> inherits from <code class="classname">ddt</code>, which allows - <span class="bold"><strong>*iter</strong></span> to return the object stored in the container. - (Technically it is an <code class="classname">ElementRef<ddt> object</code>, whose "base class" - part is the object you stored). There are a few data members and member functions in - <code class="classname">ElementRef</code>, which all start with <code class="literal">_DB_STL_</code>. To avoid - potential name clashes, applications should not use names prefixing <code class="literal">_DB_STL_</code> - in classes whose instances may be stored into dbstl containers. -</p> + <code class="classname">ElementHolder</code> should not be + used to store objects of a class because it doesn't + support access to object members using <span class="bold"><strong>(*iter).member</strong></span> or <span class="bold"><strong>iter->member</strong></span> + expressions. In this case, the default + <code class="literal">ElementRef<ddt></code> is used + automatically. + </p> <p> - Example code demonstrating this feature can be found in the - <code class="methodname">StlAdvancedFeaturesExample::arbitrary_object_storage</code> method. -</p> + <code class="classname">ElementRef</code> inherits from + <code class="classname">ddt</code>, which allows <span class="bold"><strong>*iter</strong></span> to return the object + stored in the container. (Technically it is an + <code class="classname">ElementRef<ddt> + object</code>, whose "base class" part is the + object you stored). There are a few data members and + member functions in <code class="classname">ElementRef</code>, + which all start with <code class="literal">_DB_STL_</code>. To + avoid potential name clashes, applications should not + use names prefixing <code class="literal">_DB_STL_</code> in + classes whose instances may be stored into dbstl + containers. + </p> + <p> + Example code demonstrating this feature can be + found in the + <code class="methodname">StlAdvancedFeaturesExample::arbitrary_object_storage</code> + method. + </p> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> - <h3 class="title"><a id="idp1278616"></a>Storing arbitrary sequences</h3> + <h3 class="title"><a id="idp859120"></a>Storing arbitrary sequences</h3> </div> </div> </div> + <p> + A sequence is a group of related objects, such as an + array, a string, and so forth. You can store sequences of + any structure using dbstl, so long as you implement and + register the proper callback functions. By using these + callbacks, each object in the sequence can be a complex + object with data members that are all not stored in a + continuous memory chunk. + </p> <p> - A sequence is a group of related objects, such as an array, a string, and so forth. - You can store sequences of any structure using dbstl, so long as you implement and register the - proper callback functions. By using these callbacks, each object in the sequence can be a - complex object with data members that are all not stored in a continuous memory chunk. -</p> - <p> - Note that when using these callbacks, when you retrieve a stored sequence from the database, the - entire sequence will reside in a single continuous block of memory with the same layout as that - constructed by your sequence copy function. -</p> - <p> - For example, given a type RGB: -</p> - <pre class="programlisting"> -struct RGB{char r, g, b, bright;}; </pre> + Note that when using these callbacks, when you retrieve + a stored sequence from the database, the entire sequence + will reside in a single continuous block of memory with + the same layout as that constructed by your sequence copy + function. + </p> <p> - and an array of RGB objects, the following steps describe how to store an array into one - key/data pair of a <code class="classname">db_map</code> container. -</p> + For example, given a type RGB: + </p> + <pre class="programlisting">struct RGB{char r, g, b, bright;}; </pre> + <p> + and an array of RGB objects, the following steps + describe how to store an array into one key/data pair of a + <code class="classname">db_map</code> container. + </p> <div class="orderedlist"> <ol type="1"> - <li> - Use a <code class="classname">db_map<int, RGB *, ElementHolder<RGB *> ></code> container. -</li> + <li> + Use a <code class="classname">db_map<int, RGB *, + ElementHolder<RGB *> ></code> + container. + </li> <li> <p> - Define two functions. The first returns the number of objects in a sequence, the second that - copies objects from a sequence to a defined destination in memory: - </p> + Define two functions. The first returns the + number of objects in a sequence, the second that + copies objects from a sequence to a defined + destination in memory: + </p> <pre class="programlisting">typedef size_t (*SequenceLenFunct)(const RGB*); </pre> <p> - and -</p> + and + </p> <pre class="programlisting"> typedef void (*SequenceCopyFunct)(RGB*dest, const RGB*src); </pre> </li> - <li> -Call DbstlElemTraits<RGB>::set_sequence_len_function()/set_sequence_copy_function() -to register them as callbacks. -</li> + <li> + Call + DbstlElemTraits<RGB>::set_sequence_len_function()/set_sequence_copy_function() + to register them as callbacks. + </li> </ol> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> - <h4 class="title"><a id="idp1308520"></a>The <code class="function">SequenceLenFunct</code> function</h4> + <h4 class="title"><a id="idp869312"></a>The <code class="function">SequenceLenFunct</code> + function</h4> </div> </div> </div> <pre class="programlisting">typedef size_t (*SequenceLenFunct)(const RGB*); </pre> <p> - A <code class="function">SequenceLenFunct</code> function returns the number of objects in a sequence. It - is called when inserting into or reading from the database, so there must be enough information - in the sequence itself to enable the <code class="function">SequenceLenFunct</code> function to tell how many - objects the sequence contains. The <code class="literal">char*</code> and <code class="literal">wchar_t*</code> - strings use a <code class="literal">'\0'</code> special character to do this. For example, RGB(0, 0, 0, 0) - could be used to denote the end of the sequence. Note that for your implementation of this - callback, you are not required to use a - trailing object with a special value like <code class="literal">'\0'</code> or - <code class="literal">RGB(0, 0, 0, 0)</code> to denote the end of the sequence. You are free to use - what mechanism you want in your - <code class="function">SequenceLenFunct</code> function implementation to figure out the length of the sequence. -</p> + A <code class="function">SequenceLenFunct</code> function + returns the number of objects in a sequence. It is + called when inserting into or reading from the + database, so there must be enough information in the + sequence itself to enable the + <code class="function">SequenceLenFunct</code> function to + tell how many objects the sequence contains. The + <code class="literal">char*</code> and + <code class="literal">wchar_t*</code> strings use a + <code class="literal">'\0'</code> special character to do + this. For example, RGB(0, 0, 0, 0) could be used to + denote the end of the sequence. Note that for your + implementation of this callback, you are not required + to use a trailing object with a special value like + <code class="literal">'\0'</code> or <code class="literal">RGB(0, 0, 0, + 0)</code> to denote the end of the sequence. + You are free to use what mechanism you want in your + <code class="function">SequenceLenFunct</code> function + implementation to figure out the length of the + sequence. + </p> </div> <div class="sect3" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> - <h4 class="title"><a id="idp1340280"></a>The <code class="function">SequenceCopyFunct</code> function</h4> + <h4 class="title"><a id="idp903872"></a>The <code class="function">SequenceCopyFunct</code> function</h4> </div> </div> </div> <pre class="programlisting"> typedef void (*SequenceCopyFunct)(RGB*dest, const RGB*src); </pre> <p> - <code class="function">SequenceCopyFunct</code> copies objects from the sequence - <span class="bold"><strong>src</strong></span> into memory chunk <span class="bold"><strong>dest</strong></span>. - If the objects in the sequence do not reside in a continuous memory chunk, this function must - marshal each object in the sequence into the <span class="bold"><strong>dest</strong></span> memory chunk. -</p> - <p> - The sequence objects will reside in the continuous memory chunk referred to by <span class="bold"><strong>dest</strong></span>, which has been sized by <code class="classname">SequenceLenFunct</code> - and <code class="classname">ElemSizeFunct</code> if available (which is when objects in the sequence are - of varying lengths). <code class="classname">ElemSizeFunct</code> function is not needed in this example - because <span class="bold"><strong>RGB</strong></span> is a simple fixed length type, the - <code class="literal">sizeof()</code> operator is sufficient to return the size of the sequence. -</p> + <code class="function">SequenceCopyFunct</code> copies objects + from the sequence <span class="bold"><strong>src</strong></span> + into memory chunk <span class="bold"><strong>dest</strong></span>. If the + objects in the sequence do not reside in a continuous memory chunk, this + function must marshal each object in the sequence into + the <span class="bold"><strong>dest</strong></span> memory + chunk. + </p> + <p> + The sequence objects will reside in the continuous + memory chunk referred to by <span class="bold"><strong>dest</strong></span>, which + has been sized by + <code class="classname">SequenceLenFunct</code> and + <code class="classname">ElemSizeFunct</code> if available + (which is when objects in the sequence are of varying + lengths). <code class="classname">ElemSizeFunct</code> + function is not needed in this example because + <span class="bold"><strong>RGB</strong></span> is a simple + fixed length type, the <code class="literal">sizeof()</code> + operator is sufficient to return the size of the + sequence. + </p> </div> </div> <div class="sect2" lang="en" xml:lang="en"> <div class="titlepage"> <div> <div> - <h3 class="title"><a id="idp1344912"></a>Notes</h3> + <h3 class="title"><a id="idp909008"></a>Notes</h3> </div> </div> </div> <div class="itemizedlist"> <ul type="disc"> <li> - <p> - The get and set functions of this class are not protected by any mutexes. When using - multiple threads to access the function pointers, the callback functions must be - registered to the singleton of this class before any retrieval of the callback function - pointers. Isolation may also be required among multiple threads. The best way is to - register all callback function pointers in a single thread before making use of the any - containers. - </p> + <p> + The get and set functions of this class are not + protected by any mutexes. When using multiple + threads to access the function pointers, the + callback functions must be registered to the + singleton of this class before any retrieval of + the callback function pointers. Isolation may also + be required among multiple threads. The best way + is to register all callback function pointers in a + single thread before making use of the any + containers. + </p> </li> <li> <p> - If objects in a sequence are not of identical sizes, or are not located in a consecutive - chunk of memory, you also need to implement and register the - <code class="function">DbstlElemTraits<>::ElemSizeFunct</code> callback function to measure - the size of each object. When this function is registered, it is also used when - allocating memory space. - </p> + If objects in a sequence are not of identical + sizes, or are not located in a consecutive chunk + of memory, you also need to implement and register + the + <code class="function">DbstlElemTraits<>::ElemSizeFunct</code> + callback function to measure the size of each + object. When this function is registered, it is + also used when allocating memory space. </p> <p> - There is example code demonstrating the use this feature in the - <code class="methodname">StlAdvancedFeaturesExample::arbitray_sequence_storage()</code> method. - </p> + There is example code demonstrating the use + this feature in the + <code class="methodname">StlAdvancedFeaturesExample::arbitray_sequence_storage()</code> + method. + </p> </li> <li> <p> - A consequence of this dbstl feature is that you can not store a pointer value directly - because dbstl will think it is a sequence head pointer. Instead, you need to convert the - pointer into a <code class="literal">long</code> and then store it into a <code class="literal">long</code> - container. And please note that pointer values are probably meaningless if the stored - value is to be used across different application run times. - </p> + A consequence of this dbstl feature is that you + can not store a pointer value directly because + dbstl will think it is a sequence head pointer. + Instead, you need to convert the pointer into a + <code class="literal">long</code> and then store it into + a <code class="literal">long</code> container. And please + note that pointer values are probably meaningless + if the stored value is to be used across different + application run times. + </p> </li> </ul> </div> |