Four-byte buffer in which the system returns the number of bytes that were available in the named pipe.

typedef struct _AVAILDATA {
  USHORT     cbpipe;     /*  The number of bytes that were buffered in the pipe, including the message-header bytes and bytes that have been exa
mined. */
  USHORT     cbmessage;  /*  Number of bytes in the current message. */
} AVAILDATA;

typedef   AVAILDATA   * PAVAILDATA ;