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Re: Special Data Type Declaration and Usage

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On 11/16/11 10:30 AM, Mike Copeland wrote:
> In article<op.v40apype4vph3f@gp.homenet.telecomitalia.it>,
> gennaro.prota+Usenet@gmail.com says...
>> On Tue, 15 Nov 2011 22:04:25 +0100, Mike Copeland<mrc2323@cox.net>  wrote:
>>
>>>     I need to declare an enormous array (100,000 members) of a small
>>> scalar object, and I want to populate it with default values and change
>>> some of them as needed throughout the processing.  The range of distinct
>>> values for each element is 0-15, so I could use a 4 bit "mini-byte" if
>>> something like that existed.
>>>     My question is: can I declare a bit structure data type and use it
>>> this way?  If that's possible, I don't know how to do so, nor how I'd
>>> manipulate the data values in it.  Please advise.  TIA
>>
>> Are you sure that the array is "enormous"? Using one (whole!) byte per
>> element it would occupy less than 100KiB.
>>
>     It's "enormous" to me, as I have many other large data structures in
> this program, and I have to declare it globally (it's accessed from a
> number of subprograms in several source files).  My concern is Heap
> allocation, inasmuch as there must be _some_ limit as to how much
> program data can be declared before the program chokes.

That depends on the configuration (physical and OS) of the target system.

> I;m using VS6.0, and I don't know what that limit is.

Stop right there!  An obsolete, non-standard and buggy compiler?  I'm 
sure you can do better than that.

>     I was hoping that I could cut down the total size of this data
> component and still process it efficiently.  It seems not possible...
> 8<{{

Yes you could cut down the size, but that is often orthogonal to 
efficient processing.

-- 
Ian Collins

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Special Data Type Declaration and Usage mrc2323@cox.net (Mike Copeland) - 2011-11-15 14:04 -0700
  Re: Special Data Type Declaration and Usage Ian Collins <ian-news@hotmail.com> - 2011-11-16 10:09 +1300
  Re: Special Data Type Declaration and Usage "Gennaro Prota" <gennaro.prota+Usenet@gmail.com> - 2011-11-15 22:16 +0100
    Re: Special Data Type Declaration and Usage mrc2323@cox.net (Mike Copeland) - 2011-11-15 14:30 -0700
      Re: Special Data Type Declaration and Usage Ian Collins <ian-news@hotmail.com> - 2011-11-16 10:36 +1300
        Re: Special Data Type Declaration and Usage mrc2323@cox.net (Mike Copeland) - 2011-11-15 15:02 -0700
          Re: Special Data Type Declaration and Usage Victor Bazarov <v.bazarov@comcast.invalid> - 2011-11-15 18:10 -0500
      Re: Special Data Type Declaration and Usage "Gennaro Prota" <gennaro.prota+Usenet@gmail.com> - 2011-11-15 23:58 +0100
      Re: Special Data Type Declaration and Usage Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-16 06:42 -0800
        Re: Special Data Type Declaration and Usage Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-11-16 17:16 +0000
          Re: Special Data Type Declaration and Usage Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-11-17 00:04 -0800
  Re: Special Data Type Declaration and Usage Brian Drummond <brian@shapes.demon.co.uk> - 2011-11-15 22:17 +0000
  Re: Special Data Type Declaration and Usage Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-11-15 22:19 +0000
    Re: Special Data Type Declaration and Usage Ian Collins <ian-news@hotmail.com> - 2011-11-16 11:51 +1300
      Re: Special Data Type Declaration and Usage Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-11-16 00:27 +0000
  Re: Special Data Type Declaration and Usage Paavo Helde <myfirstname@osa.pri.ee> - 2011-11-15 16:28 -0600

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