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io.RawIOBase

abstract bases

The abstract base class for raw (unbuffered) binary streams; FileIO is its implementation.

Syntax

issubclass(cls, io.RawIOBase)

You rarely hold a raw stream directly: open(path, 'rb', buffering=0) returns one, and an ordinary buffered file exposes it through its .raw attribute. Every read()/write() maps to a separate system call, and read(n) may return fewer than n bytes even before EOF, so you must loop to read the rest yourself — normal code sticks to the buffered layer and drops to raw only when it needs full control over I/O.

Examples

import io
print(issubclass(io.FileIO, io.RawIOBase))   # → True
print(issubclass(io.RawIOBase, io.IOBase))   # → True
print(issubclass(io.BufferedReader, io.RawIOBase))   # → False
print(isinstance(io.BytesIO(), io.RawIOBase))   # → False
print(hasattr(io.RawIOBase, 'readinto'))   # → True

See also

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