Reading from and Writing to the Buffer

The following table shows three fields in the MMIOINFO structure used for reading from and writing to the file I/O buffer.

┌─────────────┬─────────────────────────────────────────────┐
│Field        │Description                                  │
├─────────────┼─────────────────────────────────────────────┤
│pchNext      │Points to the next location in the buffer to │
│             │read or write.  You must increment pchNext as│
│             │you read and write the buffer.               │
├─────────────┼─────────────────────────────────────────────┤
│pchEndRead   │Identifies the location containing the last  │
│             │valid character you can read from the buffer.│
│             │This is the memory location following the    │
│             │last valid data in the buffer.               │
├─────────────┼─────────────────────────────────────────────┤
│pchEndWrite  │Identifies the last location in the buffer   │
│             │you can write to.  This is the memory        │
│             │location following the end of buffer.        │
└─────────────┴─────────────────────────────────────────────┘