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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&amp; 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&amp; GetFacetLocaleId();
    };
</codeblock> <codeblock id="GUID-57B95E9E-9071-50CC-A688-73C9781B26E4" xml:space="preserve">//myfacet.cpp
std::locale::id&amp; 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()-&gt;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 &lt;libstdcppwsd.h&gt;
#endif
int main()
    {
    __UHEAP_MARK;
    cout &lt;&lt; "Hello, World!" &lt;&lt; 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>
</related-links></concept>