Applications that define their own clipboard or DDE formats must register those formats in the system atom table to avoid conflicting with the predefined formats and any formats used by other applications. The following sample code fragment shows how to register a custom format:

#define MAX_BUF_SIZE 128

HAB hab;                               /* Anchor block handle         */
HATOMTBL hatomtblSystem;               /* System atom table handle    */
ATOM atomFormatID;                     /* Atom message                */
PSZ  pszSrc, pszDest;                  /* String pointers             */
BOOL fSuccess;
CHAR szClipString[MAX_BUF_SIZE];
APIRET rc;

/**********************************************************************/
/* Get the handle of the system atom table,                           */
/* then add the format name to the table.                             */
/**********************************************************************/

/* System atom table handle  */
hatomtblSystem = WinQuerySystemAtomTable();
/* Register format string    */
atomFormatID = WinAddAtom(hatomtblSystem,"SuperCAD_FORMAT")

/**********************************************************************/
/* Obtain data and write data to buffer (szClipString).               */
/**********************************************************************/

/* Open the clipboard */
if (WinOpenClipbrd(hab))
{

/* Allocate a shared memory object for the text data                  */
if (!(rc = DosAllocSharedMem(
     (PVOID)&pszDest,                  /* Pointer to shared memory    */
                                       /* object                      */
      (PSZ) NULL,                      /* Use unnamed shared memory   */
      (ULONG)strlen(
          szClipString) + 1,           /* Amount of memory            */
         PAG_WRITE  |                  /* Allow write access          */
         PAG_COMMIT |                  /* Commit the shared memory    */
         OBJ_GIVEABLE)))               /* Make pointer giveable       */
{

   /* Setup the source pointer to point to text */
   pszSrc = szClipString;

   /* Copy the string to the allocated memory   */
   while (*pszDest++ = *pszSrc++);

   /* Clear old data from the clipboard         */
   WinEmptyClipbrd(hab);

   /* Pass the pointer to the clipboard in custom format.             */
   /* Notice that the pointer must be a ULONG value.                  */
   fSuccess = WinSetClipbrdData(hab,   /* Anchor block handle         */
      (ULONG) pszDest,                 /* Pointer to text data        */
      atomFormatID,                    /* Custom format ID (atom)     */
      CFI_POINTER);                    /* Passing a pointer           */

   /* Close the clipboard */
   WinCloseClipbrd(hab);
}
}