Conversion Types

The string to be converted must be stored in a memory block that is accessible across processes. In Win32, this can only be accomplished by use of memory-mapped files. The global memory is created and named in the client application and the names are sent to Personal Communications through the DDE message. The steps required to implement this are demonstrated in the following example:

//Steps for a Source Buffer (done in client application)
HANDLE hMapFile;
LPVOID lpMapAddress;
ATOM   aCONV;

hMapFile = CreateFileMapping((HANDLE)0xFFFFFFFF,  // not a real file
    NULL,                                         // Default security.
    PAGE_READWRITE,                               // Read/write
    (DWORD)0,                                     // Ignored
    (DWORD)nStringLength,                         // Length of string
    (LPCTSTR)szSourceName);                       // Name of 
                                                  // mapping object.

If (hMapFile == NULL)
{
    MessageBox ("Could not create file-mapping Source object.");
    return;
}
// Now treat buffer like local memory
strcpy((LPSTR)lpMapAddress, szConcersionString);

// Repeat steps for a Target Buffer
.....
.....
// Set up ATOM information

aCONV = GlobalAddAtom("CONV"); // MUST be this string

// Post DDE Message Now ....

// When done with memory blocks, clean up
if (!UnmapViewOfFile(lpMapAddress))
{
     MessageBox ("Could not unmap view of Target.");
}

CloseHandle(hMapSFile);

// CODE ENDS