errors when passing pointers from a unit_(re)

Sat, 26 Apr 1997 23:06:36 -0700

At 03:56 PM 4/26/97 +0200, you wrote:
>According to skye:
>> 
>> var
>> 	gBuffer"^mode13VideoBuffer;
>
>You mean:  gBuffer: ^mode13VideoBuffer;-).
yah,... right 

>This I don't understand.  You mean that you are using a statically
>allocated video buffer in the Pascal program and passing a pointer to
>it to the C program?  The following should work:
>
>     Program Whatever;
>
>     Type
>       mode13VideoBuffer = array [ 1 .. 320 * 200 ] of Byte;
>       mode13VideoBufferPtr = ^mode13VideoBuffer;
>
>     Var
>       gBuffer: mode13VideoBuffer;   (* NOT a pointer to it *)
>
>     Procedure ScreenBlit ( Buffer: mode13VideoBufferPtr ); C;
>
>     begin
>       ScreenBlit ( @gBuffer );
>     end.
>
Yes, I can get that to work but what still fails is when gBuffer is
allocated using new():
var
	gBuffer:^mode13VideoBuffer; (* IS a pointer *)
.......
	new(gBuffer); 
.......
	ScreenBlit( gBuffer); (* crashes in the movedata() from the std C lib *)
.......
	dispose(gBuffer);
.......
end.

Now I'm not too sure how memory allocation works under pascal. Is this
right? I don't have many examples to got from and they all work something
like this. would this be the same as this in C:

char* gBuffer;
gBuffer = malloc(320*200);
free(gBuffer);      

>What's "false" with `New' and `GetMem'?  :-)
now I haven't seen GetMem before. The examples I'm using just use the
method i've shown above. Does GetMem work like malloc() where I can specify
the amount at runtime? (this would be nice).
Also, isn't there a limit to the amount of static variable memory I can use
(DS)? I don't want to have to fidle with my compiler options to increase
it. If I have a static array that is 64k there is potental for probles way
down the road, esp. if I have other large static structres.
 
Sorry about the basic Pascal questions. It is strange switching from C/C++
to Pascal without documentation. I keep trying to do something one way and
find out after much frustration that is done another in Pascal. I have only
a few Pascal DOCS I have found online and they all use TP. Are there any
using GPC?

>Hope this helps,
>
>    Peter
Very much, thanks.

-Skye

skye (s_c@iname.com)