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| Contributions |
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| 2021-11-01 19:19:13  AntonErtl  wrote:
| comment - Some clarifications
| see: https://forth-standard.org/standard/file/READ-LINE#contribution-216
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The "0 <= u2 <= u1" is misleading.  As becomes clear from the rest, 0 <= u2 < u1 is also guaranteed if the line terminator starts before u1 chars are received.

READ-LINE reads at most u1 characters that are not part of the line terminator.  Line terminators of up to 2 chars can occur (i.e., CRLF).  However, even with such a line terminator, it's enough to read u1+1 chars: if the line terminator does not start at the last char in the buffer, READ-LINE does not need to know if a line terminator follows right afterwards: It just returns u2=u1, no need to know about line terminators.

At least in Linux it is significantly faster to use input buffering than to always read u1+1 characters using a system call and reposition the file with another system call.

Acknowledgments: Discussions with ruv and dxforth resulted in this comment.