Known +Issues

This topic describes the known issues associated with developing Standard +C++ applications or libraries on Symbian platform.

The following functionalities of Standard C++ have certain limitations +on Symbian platform:

dynamic_cast: The dynamic_cast operator +is not fully supported on Symbian platform.
unexpected_handler: The +CodeWarrior runtime does not support the invocation of unexpected_handler upon +an exception specification violation.
IOStreams: The cin and cout objects +are instances of istream and ostream 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.

These +functions return references to the cin and cout objects +that the STL library maintains. Since they are defined as functions, an attempt +to import namespace by saying using std::cout may fail to +compile. To resolve this issue, include the entire std namespace +in such scenarios.

ARM RVCT compiler +issues with STLport

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:

Use the GCCE compiler +to generate the DEF file, if it is not available.
Ignore the warnings +generated by the ARM RVCT compiler.
When you ignore the warnings, +do not freeze the invalid export entries in the DEF file using the ARM RVCT +compiler.

Using the id +member variable of facet classes

Symbian platform does not support +exporting static data. Hence, the id member variable of facet +classes (static locale::id id) cannot be used directly +on Symbian platform. When you use these classes you must use the GetFacetLocaleId() function +to access the data member id instead.

Examples

Using the id member +of standard facets: For example, you can change locale::id Id1 += numpunct<char>::id; to locale::id Id1 += numpunct<char>::GetFacetLocaleId();.
Deriving a class +from a standard facet: Declare a GetFacetLocaleId() static +method, in addition to the member variable ID, when you define a class that +is inherited from the locale::facet class, as illustrated +in the following code:
class myfacet : public locale::facet + { + public: + static locale::id id; + static locale::id& GetFacetLocaleId() + { + return id; + } + };
Using a class that +is part of a DLL: Ensure that you also handle the Writable Static Data +(WSD) issues for emulator (WINSCW) builds along with the issues described +in examples 1 and 2 as illustrated in the following code:
//myfacet.h +class myfacet : public locale::facet + { + public: +#ifndef __WINSCW__ + static locale::id id; +#endif + static locale::id& GetFacetLocaleId(); + }; + //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 + }

Using memory +leak detection macros

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 __UHEAP_MARK and __UHEAP_MARKEND, +then you get a panic at __UHEAP_MARKEND.

To avoid +this panic, you must call the CleanupWSD() function, provided +only for use on emulator. For more information about how to achieve this, +see the following example code:

#include <iostream> +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; + }