Windows CE (STL + std::bad_alloc + CMemoryException, ...)

[Erakis]

Hi,

I'm building an application for Windows CE and Windows Desktop. The cross compilation is possible using some preprocessor directive, a different VS project file and a different VS solution file.

As my application must be robust, I need to test each memory allocation and in the case of an memory allocation failure . I want to be able to correctly clean the previously allocated resources.

Here is an exemple to show you my actual problem :

#include <list>
using namespace std;

typedef struct _MyObject
{
    int a[9999];
} MyObject;

int i = 0;
MyObject p;
list<MyObject> v;
try
{
    // Force failure
    for (; i < 999999; ++i)
    {
        v.push_back(p);
    }
}
catch(CMemoryException* er)
{
    DEBUG_ALERT("CMemoryException !");
}
catch(std::bad_alloc& er)
{
    DEBUG_ALERT("bad_alloc error !");
}

And the following file (NewHandler.cpp) is only include on Windows CE (To force a std::bad_alloc) uppon a memory failure. As Windows CE malloc returns NULL instead of throwing std::bad_alloc exception.

// http://msdn.microsoft.com/en-us/magazine/cc164087.aspx
#include <new>
#include <new.h>

// 4073: initializers put in library initialization area
#pragma warning(disable: 4073)

#pragma init_seg(lib)

namespace
{

   int new_handler(size_t) 
   {
       throw std::bad_alloc();
       return 0;
   }

   class NewHandler
   {
   public:
       NewHandler() 
       {
           m_old_new_handler = _set_new_handler(new_handler);
       }
    
       ~NewHandler() 
       {
          _set_new_handler(m_old_new_handler);
       }

   private:
       _PNH m_old_new_handler;

   } g_NewHandler; 
}

On Windows Desktop the program allocate memory until a CMemoryException is thrown. This is the result I want also on Windows CE.

On Windows CE, the program allocate memory until the device show a popup message with the message "Memory system is very low". So I cannot intercept the moment when the first allocation failed ! Result, my program crash and the device too ! Not wise !.

Is there any way to circumvent this problem ?

I don't understand how can we catch memory problem on Windows CE, if we have NO WAY to detect it ? Take the list container as exemple, the push_back function returns nothing (void) and it doesn't throw any exeption when failing. So how can I more secure my code about allocation failure ?

Best regards,
Martin