Stream buffers can impose constraints. The constraints include:
- The input sequence can be not readable
- The output sequence can be not writable
- The sequences can be associated with other presentations such as external files
- The sequences can support operations to or from associated sequences.
- The sequences can impose limitations on how the program can read and write characters to and from a sequence or alter the stream position.
There are three pointers that control the operations performed on a sequence or associated sequences. These are used for read, writes and stream position alteration. If not
null all pointers point to the same
charT array object.
- The beginning pointer or lowest element in an array. - (
beg)
- The next pointer of next element addressed for read or write. - (
next)
- The end pointer of first element addressed beyond the end of the array. - (
end)