Prolog: get vs. at_end_of_stream for checking end of file

Question

I am reading a file using prolog and was wondering about the difference of saying:

processRead(Stream, ...) :- at_end_of_stream(Stream), !.

and:

processRead(Stream, ...) :- get(Stream, Ch), Ch is -1, !.

Is there any?

Answer 1

First things first! Follow @mat's advice!

If you need to chose, always prefer using at_end_of_stream/1 over get/2!

• get/2 is deprecated. If you have decade-old legacy code, migrate it.

  If your code is new, don't ever use it. Never. Not even once.

• at_end_of_stream/1 is defined by the iso-prolog standard.
• Virtually every modern Prolog processor supports at_end_of_stream/1—including (but not limited to) GNU Prolog, SICStus Prolog, SWI Prolog, B-Prolog, and Eclipse CLP.