CODEWITHSUNDEEP
cstream
joao victor Rosmaninho
joao victor Rosmaninho

Reputation: 33

Streams and abstraction

I'm studying about C (ANSI) I/O and C (Unix) I/O and I have the following question:

If everything on a computer without abstraction is a stream of data(or dataflow, call it what you want), regardless of whether it came from a file or a socket, why do I need an abstraction layer called stream to handle this?

Upvotes: 0

Views: 225

Answers (2)

John Bollinger
John Bollinger

Reputation: 180266

I'm studying about C ansi I/O and C unix I/O and i had the following question:

if everything on a computer without abstraction is a stream of data(or dataflow, call it what you want), regardless of whether it came from a file or a socket, why do I need an abstraction layer called stream to handle this?

I think you are confused about where the key abstraction lies: it is exactly the embodiment of the UNIX design philosophy that "everything is a file", realized in part by the fact that one set of low-level POSIX I/O functions handles all devices. Using those I/O functions is not accessing the computer without (device) abstraction.

On a POSIX system, you do not need streams, but it is often convenient to use them, at least because

  1. they provide a richer, higher-level abstraction than raw I/O does, and
  2. they are more portable to non-POSIX systems.

On a non-POSIX system you possibly do need streams, because the low-level POSIX I/O functions may not exist. The latter are not specified by the C language standard, but rather by POSIX.

Upvotes: 0

rici
rici

Reputation: 241731

There are no abstractions inside a machine. The abstractions are all inside your head. "Dataflow" is an abstraction you use to think about very distinct mechanisms; if you view a computer "without abstractions", you won't see any "streams of data".

The "abstraction layer" is a concrete interface designed to make a bunch of complicated and idiosyncratic mechanisms controllable in a way which corresponds to the abstraction you use to design programs.

Upvotes: 2

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