Dynamic-data-exchange control structure.

typedef struct _DDESTRUCT {
  ULONG      cbData;         /*  Length of the data. */
  USHORT     fsStatus;       /*  Status of the data exchange. */
  USHORT     usFormat;       /*  DDE data format. */
  USHORT     offszItemName;  /*  Offset to item name. */
  USHORT     offabData;      /*  Offset to beginning of data. */
} DDESTRUCT;

typedef   DDESTRUCT   * PDDESTRUCT ;

DDE formats, specified in the usFormat parameter, are registered with the atom manager, using the system atom table. The predefined DDE formats are guaranteed not to conflict with the values returned by the atom manager.

Applications can define their own data formats; however, each nonstandard DDE format must have a unique identification number. To receive an identification number for a nonstardard format, the application must register the name of the format in the system atom table. Other applications that have the name of the format can then query the system atom table for the format's identification number. This method ensures that all applications use the same atom to identify a format.