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Subject: Re: Engine programming - standard input

Author: Matt Thomas

Date: 22:46:17 12/03/03

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On December 03, 2003 at 11:55:37, Dieter Buerssner wrote:

>On December 03, 2003 at 09:43:38, Robert Hyatt wrote:
>
>>On December 03, 2003 at 05:08:14, Matt Thomas wrote:
>>
>>>I want to create a chess engine and am starting with the input/output routines.
>>>I can handle output, but am not sure about how to implement input.  I am
>>>thinking to use ReadFile() to be unbuffered, and for pipes.  I could implement a
>>>loop to poll for input, but wouldn't that be a drag on CPU cycles?
>
>The typical method would be, to poll for input not all the time, but say for
>example every 10000 nodes. The overhead will be small. The number 10000 can be
>dynamically adjusted to the CPU and the time left. I would suggest, to not use
>system specific functions for reading the input (for seeing if input is
>available, system specific means are needed in C). So, instead of ReadFile,
>perhaps fgets() or fgetc() (which are Standard C functions and portable to any
>system). I use mainly fgets().
>

I like the idea of using using some timer operation to poll input.  I want to
review input/output commands.  I am programming on Win98, but I also have
Mandrake,Win2k,XP, so it would be nice to have cross-platform/OS capabilities.
I want to review threads also, they offer some interesting possibilities.

>>1.  use Read().
>
>I guess Robert means read(). As said above, I would prefer Standard C functions
>(if possible). read() is not a Standard C function. When using Standard C
>functions, you probably must also set the buffer method for stdin to
>non-buffered (perhaps line buffered is sufficient, because the WB-protocol uses
>whole lines for all commands). For example with the Standard C function
>setvbuf().
>
>If done slightly careful, a WB-engine could be written with Standard C means
>besides the input polling and some time function (practically a good resolution
>of the times will be needed, especially when playing faster time controls).

Yep, read about the bufferless situation from the Winboard protocol notes.  I
remember read() being a suggestion in those notes.  I have to look around for my
Bjarne Stroustrup book to review the standard.  Been a while.  Thanks for
sharing your thoughts, Matt



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