Streams

A stream represents the transmission of data from one side to another. A file represents a place for storing data on disk. A file uses streams to store and load data. A buffer is used temporarily to store data from the stream.

Characters written to or read from an unbuffered stream are transmitted individually to or from the file as soon as possible. Characters written to or read from a fully buffered stream are transmitted to or from the file in blocks of arbitrary size. Characters written to a line buffered stream are transmitted to the file in blocks when a new line appears.

Low-Level File Operations - Unbuffered Stream

The methods open(), read(), write(), lseek() are part of the unistd.h library. They work with the file descriptor (INT) and treat the input/output stream as binary data.

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Low-Level File Operations - Buffered Stream

The methods fopen(), fread(), fwrite(), fseek() are part of the stdio.h library. They use the FILE object type and treat the input/output stream as text. Read/write operations on the accumulated buffer can be forced using the fflush() method.

04_streams_fig2.png