Subject: Re: Q:GSoft & MemManager
Newsgroups: comp.sys.apple2.programmer
From: dempson@actrix.gen.nz (David Empson)
Date: Fri, 24 Dec 1999 11:49:45 +1300
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Al Crout <acrout@vcn.bc.ca> wrote:

> I would like to use the SUB BlockMove in a program but my code
> produces "parameter type mismatch at parameter 1" error msg.

>       DIM MEM AS LONG
>       MEM(1) = $00E19E00:! COLOR PALETTE 0
>       MEM(2) = $00E19E20:! COLOR PALETTE 1
>       MEM(3) = $00000005:! MOVE $20 BYTES
>  
>       BLOCKMOVE (@MEM(1), @MEM(2), MEM(3))

Forgive me if I've missed some details, since I'm not familiar with
GSoft, but I don't think this would work (even if there wasn't a
"parameter mismatch" error).

For starters, why are you claiming that a count of 5 will move $20 (32)
bytes?

Secondly, if I'm correct in assuming that the '@' operator means the
same as Pascal's '@' operator and C's '&' operator (get the address of a
variable), then you are actually trying to move the contents of the MEM
array itself, not the colour palettes.

I don't understand why it is claiming a type mismatch, unless BlockMove
is prototyped as expecting a "Ptr", which is a "pointer to a byte" (like
in C), not a generic "pointer to anything".  In this case, the '@'
operator may be resulting in a type of "pointer to long".  You need to
type-cast MEM(1) and MEM(2) into a pointer, not get the address of them.

Another possibility might be if you've neglected to include a file which
provides GSoft with a prototype of the BlockMove function.  In C, it
would be necessary to include <Memory.h> or <MemMgr.h> (I forget its
exact name), and in Pascal, it would be necessary to refer to the
corresponding interface unit in a Uses directive.

This is how I would do it in C, sticking to the array:

void demo(void)
{
  long MEM[3];

  MEM[0] = 0x00E19E00;
  MEM[1] = 0x00E19E20;
  MEM[2] = 0x00000020;
  BlockMove((Ptr)MEM[0], (Ptr)MEM[1], MEM[2]);
}

In Pascal (I'm a little rusty, so some details may be slightly off):

Procedure Demo;
Var
  MEM : Array[1..3] of Longint;
Begin
  MEM[1] := $00E19E00;
  MEM[2] := $00E19E20;
  MEM[3] := $00000020;
  BlockMove(Ptr(MEM[1]), Ptr(MEM[2]), MEM[3]);
End;

You'll need to work out the corresponding syntax for GSoft to do a
"typecast to Ptr".

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P O Box 27-103, Wellington, New Zealand