Re: Delayed "printf"

From	Grant Edwards <invalid@invalid.invalid>
Newsgroups	comp.arch.embedded
Subject	Re: Delayed "printf"
Date	2017-04-26 17:38 +0000
Organization	PANIX Public Access Internet and UNIX, NYC
Message-ID	<odqlts$i4p$2@reader1.panix.com> (permalink)
References	<R6WdnUr9KJ3rBmPFnZ2dnUU7-K2dnZ2d@giganews.com> <1876899119.514920107.746879.acolvin-efunct.com@news.eternal-september.org> <odqlsa$i4p$1@reader1.panix.com>

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On 2017-04-26, Grant Edwards <invalid@invalid.invalid> wrote:
> On 2017-04-26, mac <acolvin@efunct.com> wrote:
>>> Just how dumb is it to have "printf" queue up the format string AND the 
>>> parameters into a buffer, to be printed out in some low-priority task?  
>>> For a system with sufficient memory, this seems like an astonishingly 
>>> sensible thing to me.
>>
>> It's so dumb that I do it often. Usually as a ring buffer of {format string
>> ptr, arg...} with a fixed limit on the number of args. Sometime I actually
>> do the print offline, from coredumps or shared memory.
>
> I do something similar.  In the latest incarnation, there's a
> dedicated sourceid/instance index, two 32-bit "parameters", and the
> printf "format" string is limited to somehting like 16 bytes.
>
> There's a C macro that puts that stuff into a circular buffer in
> shared memory.  Then there is a seperate utility to print the buffer
> contents.

If you want to save even more time/space, you can require that the
format string have a static lifetime, and just copy a pointer into the
circular buffer.

-- 
Grant Edwards               grant.b.edwards        Yow! You mean you don't
                                  at               want to watch WRESTLING
                              gmail.com            from ATLANTA?

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Delayed "printf" Tim Wescott <seemywebsite@myfooter.really> - 2017-04-24 19:42 -0500
  Re: Delayed "printf" Don Y <blockedofcourse@foo.invalid> - 2017-04-24 18:51 -0700
    Re: Delayed "printf" Tim Wescott <tim@seemywebsite.com> - 2017-04-24 21:54 -0500
      Re: Delayed "printf" Don Y <blockedofcourse@foo.invalid> - 2017-04-24 21:27 -0700
  Re: Delayed "printf" Paul Rubin <no.email@nospam.invalid> - 2017-04-24 19:53 -0700
  Re: Delayed "printf" Clifford Heath <no.spam@please.net> - 2017-04-25 13:01 +1000
    Re: Delayed "printf" Theo Markettos <theom+news@chiark.greenend.org.uk> - 2017-04-25 18:51 +0100
      Re: Delayed "printf" Clifford Heath <no.spam@please.net> - 2017-04-26 12:59 +1000
        Re: Delayed "printf" Theo Markettos <theom+news@chiark.greenend.org.uk> - 2017-04-26 13:24 +0100
  Re: Delayed "printf" Robert Wessel <robertwessel2@yahoo.com> - 2017-04-25 00:19 -0500
    Re: Delayed "printf" David Brown <david.brown@hesbynett.no> - 2017-04-25 10:44 +0200
      Re: Delayed "printf" Robert Wessel <robertwessel2@yahoo.com> - 2017-04-25 09:22 -0500
        Re: Delayed "printf" David Brown <david.brown@hesbynett.no> - 2017-04-25 16:37 +0200
    Re: Delayed "printf" Tim Wescott <tim@seemywebsite.com> - 2017-04-25 10:49 -0500
  Re: Delayed "printf" Jack <jack4747@gmail.com> - 2017-04-24 23:33 -0700
  Re: Delayed "printf" Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-04-25 08:09 +0100
  Re: Delayed "printf" John Devereux <john@devereux.me.uk> - 2017-04-25 08:14 +0100
  Re: Delayed "printf" David Brown <david.brown@hesbynett.no> - 2017-04-25 10:58 +0200
  Re: Delayed "printf" Stefan Reuther <stefan.news@arcor.de> - 2017-04-25 18:46 +0200
  Re: Delayed "printf" Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2017-04-25 21:03 +0200
  Re: Delayed "printf" Tim Wescott <seemywebsite@myfooter.really> - 2017-04-25 16:11 -0500
    Re: Delayed "printf" Les Cargill <lcargill99@comcast.com> - 2017-04-25 17:28 -0500
    Re: Delayed "printf" Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-04-26 10:03 +0300
  Re: Delayed "printf" Dave Nadler <drn@nadler.com> - 2017-04-25 14:31 -0700
  Re: Delayed "printf" Les Cargill <lcargill99@comcast.com> - 2017-04-25 17:25 -0500
  Re: Delayed "printf" mac <acolvin@efunct.com> - 2017-04-26 17:22 +0000
    Re: Delayed "printf" Grant Edwards <invalid@invalid.invalid> - 2017-04-26 17:37 +0000
      Re: Delayed "printf" Grant Edwards <invalid@invalid.invalid> - 2017-04-26 17:38 +0000

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