Print Page - buffering of (print)

Title: buffering of (print)
Post by: Dmi on March 12, 2008, 03:11:51 AM

Hi, Lutz!

Just discover that

Code Select Expand
(while true (print ".") (sleep 1000))

started in command prompt shows all the output only after execution is finished.

Often this is not useful.

If this is a new behavior, then something like (flush), or, better, the output buffer configuration for particular handle, like in perl, will be a good addition.

Title:
Post by: Lutz on March 12, 2008, 04:38:31 AM

On Unix Mac OS X you can import fflush()

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> (import "libc.dylib" "fflush")
fflush <948F88C7>
> (while true (print ".") (fflush 0) (sleep 200))
................................................^Creceived SIGINT - in function sleep
(c)ontinue, (d)ebug, e(x)it, (r)eset:r
>

The SIGINT was caused by hitting Ctrl-C. The above is on Mac OS X. On Linux you would use: libc.so. On Win32 something else?

ps: output is also forced with line-feeds

Title:
Post by: Dmi on March 12, 2008, 05:30:05 AM

Thanks.

Title:
Post by: Lutz on March 12, 2008, 06:16:19 AM

... and you can also use 'write-buffer' on stdout and don't need to flush:

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> (while true (write-buffer 0 ".") (sleep 200))
..................^Creceived SIGINT - in function sleep
(c)ontinue, (d)ebug, e(x)it, (r)eset:x
~>

Title:
Post by: Dmi on March 12, 2008, 07:05:58 AM

oh! write-buffer is sufficient! thanks again!

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Forum => newLISP newS => Topic started by: Dmi on March 12, 2008, 03:11:51 AM