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<concept id="GUID-D32E52C9-F05C-5F1E-8B49-243D555C353C" xml:lang="en"><title>Known

Issues</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<p>This topic describes the known issues associated with developing Standard

C++ applications or libraries on the Symbian platform. </p>

<p>The following functionalities of Standard C++ have certain limitations

on the Symbian platform: </p>

<ul>

<li id="GUID-8A496C80-74F0-559D-84B3-34EF8BA15A39"><p> <b>dynamic_cast:</b> The <codeph>dynamic_cast</codeph> operator

is not fully supported on the Symbian platform. </p> </li>

<li id="GUID-012F6B22-4A66-5B54-B981-01A252F10147"><p> <b>unexpected_handler:</b> The

CodeWarrior runtime does not support the invocation of <codeph>unexpected_handler</codeph> upon

an exception specification violation. </p> </li>

<li id="GUID-9FF61C6B-21D4-521D-A1FF-086D28FDAADF"><p> <b>IOStreams:</b> The <codeph>cin</codeph> and <codeph>cout</codeph> objects

are instances of <codeph>istream</codeph> and <codeph>ostream</codeph> classes

and are exported by the STL library. As the emulator tool-chain does not support

exporting of data, these are defined as function calls on the emulator. </p> <p>These

functions return references to the <codeph>cin</codeph> and <codeph>cout</codeph> objects

that the STL library maintains. Since they are defined as functions, an attempt

to import namespace by saying using <codeph>std::cout</codeph> may fail to

compile. To resolve this issue, include the entire <codeph>std</codeph> namespace

in such scenarios. </p> </li>

</ul>

<section id="GUID-EB8B9B0E-0971-4147-B8FB-94F2D602B61F"><title>ARM RVCT compiler

issues with STLport</title><p>Due to a defect in the ARM RVCT compiler versions

2.2, 3.1 and 4.0, building STLport v5 or STLport-based applications, creates

some invalid export entries in DEF files. To workaround this issue, perform

the following steps:</p><ol>

<li id="GUID-6BD383B8-C6C8-4C08-A741-2D90C21D274F"><p>Use the GCCE compiler

to generate the DEF file, if it is not available.</p></li>

<li id="GUID-EA6CD191-69CA-4AA5-80FB-704F52F583F6"><p>Ignore the warnings

generated by the ARM RVCT compiler.</p><note>When you ignore the warnings,

do not freeze the invalid export entries in the DEF file using the ARM RVCT

compiler.</note></li>

</ol></section>

<section id="GUID-6008A836-2454-49E5-BE25-29EB9074CF88"><title>Using the id

member variable of facet classes</title> <p>The Symbian platform does not

support exporting static data. Hence, the <codeph>id</codeph> member variable

of facet classes (<codeph>static locale::id           id</codeph>) cannot

be used directly on the Symbian platform. When you use these classes you must

use the <codeph>GetFacetLocaleId()</codeph> function to access the data member <codeph>id</codeph> instead. </p> <p> <b>Examples</b>  </p> <ol id="GUID-96B64FD3-382E-56E1-BAD6-90DFBDA0969F">

<li id="GUID-20337C94-A194-5BD7-9974-490C1EBB543F"><p> <b>Using the id member

of standard facets:</b> For example, you can change <codeph>locale::id Id1

=                 numpunct&lt;char&gt;::id;</codeph> to <codeph>locale::id Id1

=                 numpunct&lt;char&gt;::GetFacetLocaleId();</codeph>. </p> </li>

<li id="GUID-F91F6741-FA71-5644-BE02-717E5872B293"><p> <b>Deriving a class

from a standard facet:</b> Declare a <codeph>GetFacetLocaleId()</codeph> static

method, in addition to the member variable ID, when you define a class that

is inherited from the <codeph>locale::facet</codeph> class, as illustrated

in the following code: </p> <codeblock id="GUID-692D5326-4048-52DC-8347-5006CBEFAF0F" xml:space="preserve">class myfacet : public locale::facet

    {

    public:

    static locale::id id;

    static locale::id& GetFacetLocaleId() 

        {

        return id;

        } 

    };</codeblock> </li>

<li id="GUID-600D7CAC-C9C5-5722-987A-66FE6E2D7D01"><p> <b>Using a class that

is part of a DLL:</b> Ensure that you also handle the Writable Static Data

(WSD) issues for emulator (WINSCW) builds along with the issues described

in examples <b>1</b> and <b>2</b> as illustrated in the following code: </p> <codeblock id="GUID-8307FD25-D980-5FC1-A0FB-83098BE5D331" xml:space="preserve">//myfacet.h

class myfacet : public locale::facet

    {

    public:

#ifndef __WINSCW__  

    static locale::id id;

#endif

    static locale::id& GetFacetLocaleId();

    };

</codeblock> <codeblock id="GUID-57B95E9E-9071-50CC-A688-73C9781B26E4" xml:space="preserve">//myfacet.cpp

std::locale::id& myfacet::GetFacetLocaleId()

    {

#ifndef __WINSCW__  

    return id;

#else

    // get the WSD struct – uses EWSD solution

    // get_wsd_struct() is a function defined by

                // the user to get a pointer to his WSD struct.

    return get_wsd_struct()->myfacet_id;

#endif

    }</codeblock> </li>

</ol> </section>

<section id="GUID-35767460-AE19-47D2-B24F-0CFEC8B999EF"><title>Using memory

leak detection macros</title> <p>On an emulator, there are some dynamic memory

allocations made for supporting WSD, when the Standard C++ library is initialised.

In this scenario, if you add a memory leak detection macro, such as <codeph>__UHEAP_MARK</codeph> and <codeph>__UHEAP_MARKEND</codeph>,

then you get a panic at <codeph>__UHEAP_MARKEND</codeph>. </p> <p>To avoid

this panic, you must call the <codeph>CleanupWSD()</codeph> function, provided

only for use on emulator. For more information about how to achieve this,

see the following example code: </p> <codeblock id="GUID-52610746-62BA-5EDB-A584-091CD6724260" xml:space="preserve">#include &lt;iostream&gt;

using namespace std;

#ifdef __WINSCW__

#include <libstdcppwsd.h>

#endif

int main()

    {

    __UHEAP_MARK;

    cout << "Hello, World!" << endl;

#ifdef __WINSCW__

    CleanupWSD();// Cleanup all WSD related allocations

#endif

    __UHEAP_MARKEND;

    return 0;

    }</codeblock> </section>

</conbody><related-links>

<link href="GUID-D6BEAF0D-844D-51F4-8DB7-FB1D60E17FE3.dita"><linktext>Copyright

Acknowledgments for Standard C++                 (STLport)</linktext></link>

<link href="GUID-F7FEB759-E64D-5B6D-9017-C5E982E4FC16.dita"><linktext>Standard

C++ Library Overview</linktext></link>

<link href="GUID-2CCD1748-9EDE-5383-9941-A3051E06F3E2.dita"><linktext>Standard

C++ Support on the Symbian platform</linktext></link>

<link href="GUID-CDE8CD85-8467-5B36-A0AC-41D1D98151CA.dita"><linktext>Developing

Applications or Libraries                 Using Standard C++</linktext></link>

<link href="GUID-E331B72B-84AF-558A-9B8F-73E5E50B58C7.dita"><linktext>Building

a Standard C++ Application or                 Library</linktext></link>

<link href="GUID-5B3F5296-D6D0-5D25-8362-141DF5927E52.dita"><linktext>Troubleshooting</linktext>

</link>