Question

I am trying to write into a (shared) named file mapping object like so:

//ENTER CRITICAL SECTION FIRST
int ncbSzMapping = 0x92B8;    //Size of a shared struct

hFileMapping = CreateFileMapping((HANDLE)INVALID_HANDLE_VALUE,
    NULL, PAGE_READWRITE, 
    0, ncbSzMapping, 
    _T("mapping_name"));
if(hFileMapping)
{
    BYTE* pRWData = MapViewOfFile(hFileMapping, 
        FILE_MAP_ALL_ACCESS, 0, 0, ncbSzMapping);
    if(pRWData)
    {
        //Write data into 'pRWData' of 'ncbSzMapping' bytes

        UnmapViewOfFile(pRWData);
    }
}

...
//LEAVE CRITICAL SECTION

The code above works without a problem. But when I change the ncbSzMapping to 0x8A8B8 the code above succeeds but later down the code I get an exception c00000fd right before a function call that makes no sense to me.

Any idea why that size increase makes a difference and how to fix it?

Answer 1

0xc00000fd is a stack overflow. Are you declaring a buffer as a local variable with that size? If so, that’s your problem. Move the buffer off the stack by making it a global or static, or allocate it dynamically using new/delete.