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From: bobb@vice.ICO.TEK.COM (Bob Beauchaine)
Newsgroups: comp.lang.pascal
Subject: Re: need dynamic array on heap
Message-ID: <7309@vice.ICO.TEK.COM>
Date: 18 Apr 91 16:25:02 GMT
References: <1991Apr12.234843.9031@ux1.cso.uiuc.edu> <4816@gumby.Altos.COM> <7294@vice.ICO.TEK.COM> <91107.174405SPRAGGEJ@QUCDN.QueensU.CA>
Reply-To: bobb@vice.ICO.TEK.COM (Bob Beauchaine)
Organization: Tektronix, Inc., Beaverton,  OR.
Lines: 35

In article <91107.174405SPRAGGEJ@QUCDN.QueensU.CA> SPRAGGEJ@QUCDN.QueensU.CA (John G. Spragge) writes:
>In article <7294@vice.ICO.TEK.COM>, bobb@vice.ICO.TEK.COM (Bob Beauchaine) says:
>>
>>  type byte_buf = array[1..64000] of byte;
>>       byte_buf_ptr = ^byte_buf;
>>
>>  var  buffer : pointer;
>>  .
>>  .
>>  getmem(buffer,somesize); { Allocate only as many bytes as you need }
>>  byte_buf_ptr(buffer)^[2] := somevalue;
>
>Actually, since GETMEM takes ANY pointer type, you don't need
>the typecast. You don't have to allocate enough memory for the
>structure you're loading; you just have to be sure your code
>will manage dynamic structures correctly.
>

  You most certainly do need the typecast.  Notice the getmem call
  does not use the typecast; it's the reference to the pointer
  as a pointer to an array of bytes that requires the typecast.
  Guess you weren't reading too close :).

  As I said, I use this method frequently.  You don't get a free 
  lunch; bypassing Pascal's strong type checking takes a little
  more work.



/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ 

Bob Beauchaine bobb@vice.ICO.TEK.COM 

C: The language that combines the power of assembly language with the 
   flexibility of assembly language.