Pascal Question
Error while deleting 3D dynamic array in Pascal
The point is to make it work with pointers. Also, I found similar problem with C++. Its not working with Pascal, well, I prob. missed something.
1) I make types and variable for my pointers:
type
PReal = ^double;
PPReal = ^PReal;
var
data : ^PPReal;
2) This is how I allocate memory (x,y,z are dimensions):
GetMem( data, sizeof(PPReal)*x );
for i:=0 to x-1 do begin
GetMem( (data+i)^, sizeof(PReal)*y );
for j:=0 to y-1 do begin
GetMem( ((data+i)^+j)^, sizeof(real)*z );
end;
end;
3) And this is how I try to Dispose() it:
for i:=0 to x-1 do begin
for j:=0 to y-1 do begin
Dispose( ((data+i)^+j) );
end;
Dispose( (data+i) );
end;
Dispose( data );
However, I'm getting 216(memory access) or 204(invalid pointer operation) runtime errors. Like this. Full code (FreePascal IDE)
Any help appreciated.
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Answer Source
The last dispose is mirrored to its getmem, but the other two not. Fix that and it works:
for i:=0 to x-1 do begin
for j:=0 to y-1 do begin
writeln(i,' ',j,' *');
Dispose( ((data+i)^+j)^ );
end;
writeln(i,' ',j);
Dispose( (data+i)^ );
end;
Dispose( data );
p.s. freemem is the logical companion to getmem, as dispose is to new.
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