> How do I access the memory allocated by this statement :

> getmem(apointer, 1024);

> Please don't tell me it works like this :

> apointer^[0] := 56;

> because this doesn't work - I'm using TP6 if it helps.

>squigger wrote:

>> How do I access the memory allocated by this statement :

>> getmem(apointer, 1024);

>> Please don't tell me it works like this :

>> apointer^[0] := 56;

>> because this doesn't work - I'm using TP6 if it helps.

>You should declare or typecast apointer to whatever it
>is you're storing in your memory.  The most general way
>would be:

>type
>   memarray = array[0..$FFF0] of byte;
>   memptr = ^memarray;
>var
>   apointer : memptr;

>...

> getmem(apointer, 1024);
> apointer^[57] := 42;

>Not that in this general case apointer^[1025] will not
>give you a range check error.

>Hope this helps,
>Jochen

>>squigger wrote:

>>> How do I access the memory allocated by this statement :

>>> getmem(apointer, 1024);

>>> Please don't tell me it works like this :

>>> apointer^[0] := 56;

>>> because this doesn't work - I'm using TP6 if it helps.

>>You should declare or typecast apointer to whatever it
>>is you're storing in your memory.  The most general way
>>would be:

>>type
>>   memarray = array[0..$FFF0] of byte;
>>   memptr = ^memarray;
>>var
>>   apointer : memptr;

>>...

>> getmem(apointer, 1024);
>> apointer^[57] := 42;

>>Not that in this general case apointer^[1025] will not
>>give you a range check error.

>>Hope this helps,
>>Jochen

>Thanks.  Now, how do I use this for a random amount (as in a sprite
>programme)?
>Or can't it be done (wouldn't surprise me...)

>squigger hops again

>On 19 Mar 97 22:02:36 GMT, jas...@athena.sunitafe.edu.au (squigger)
>wrote:

>>In article <332FD303....@berlin.snafu.de>, joch...@berlin.snafu.de
>>says...

>>>squigger wrote:

>>>> How do I access the memory allocated by this statement :

>>>> getmem(apointer, 1024);

>>>> Please don't tell me it works like this :

>>>> apointer^[0] := 56;

>>>> because this doesn't work - I'm using TP6 if it helps.

>>>You should declare or typecast apointer to whatever it
>>>is you're storing in your memory.  The most general way
>>>would be:

>>>type
>>>   memarray = array[0..$FFF0] of byte;
>>>   memptr = ^memarray;
>>>var
>>>   apointer : memptr;

>>>...

>>> getmem(apointer, 1024);
>>> apointer^[57] := 42;

>>>Not that in this general case apointer^[1025] will not
>>>give you a range check error.

>>>Hope this helps,
>>>Jochen

>>Thanks.  Now, how do I use this for a random amount (as in a sprite
>>programme)?
>>Or can't it be done (wouldn't surprise me...)

>>squigger hops again

>Try the MOVE procedure ...

>move(var source, dest; count : word)

>move copies a block of  'count' bytes starting at the first byte of
>'source' into the space starting at the first byte of  'dest'  .  

>'source' could be the entity you generate w/ getmem,  an element
>within an array, a position within a string, etc.  likewise with
>'dest'.

>BTW, using the sizeof  function is the safe way to define count

>Nick

>Thanks.  Now, how do I use this for a random amount (as in a sprite
>programme)?
>Or can't it be done (wouldn't surprise me...)

>In article <3330627...@ren2.netconnect.com.au> of Wed, 19 Mar 1997
>22:02:36 in comp.lang.pascal.borland, squigger

>>Thanks.  Now, how do I use this for a random amount (as in a sprite
>>programme)?
>>Or can't it be done (wouldn't surprise me...)

>The following compiles and runs, apparently correctly.  It makes V
point
>to a random-sized byte array and reads a random byte which may or may
>not be within the allocated array.  ISTM that it it is range-check safe
>:-( .
>        program xx ;
>        type AB = array [0..$FFF0] of byte ;
>          PAB = ^AB ;
>        var V : PAB ; B : byte ;
>        begin Write('A') ; Randomize ;
>          GetMem(V, random($FFF1)) ;
>          B := V^[random($FFF1)] ;
>          Writeln('B') ; Readln end.

>Is this random enough as a demonstration?
>--
>John Stockton, Surrey, UK.    j...@merlyn.demon.co.uk    Turnpike v1.12
   MIME.
>  Web URL: http://www.merlyn.demon.co.uk/ -- includes FAQqish topics
and links.
>  Standard signature separator is as above, a line comprising "-- "
(SoRFC1036)
>  Standard quoter : ">" / "> " recognised by most good news readers

>On 20 Mar 97 21:59:14 GMT, jas...@athena.sunitafe.edu.au (squigger)
>wrote:

>>But that wastes memory, doesn't it?  I'm not sure...

>The creation of an array  type does NOT allocate memory for each
>element in the array ....  it just defines a structure that COULD
>access those elements.  Even if you define a [1..$FFF0] array, you
>can't use the $F000'th element unless you Getmem'd at least a $F000
>sized space...

>As to use, use it like any other pointer referenced string of bytes!

>Nick

>But that wastes memory, doesn't it?  I'm not sure...

>Thanks, I can see how that works (for once!  Yippee! I understand it!).
>But that wastes memory, doesn't it?  I'm not sure...