delphi - Correctly allocating/freeing memory for records in static array -


yesterday had memory corruption going on , i'm highly suspect of how record arrays being allocated , deallocated. short version demostration:

type   tmyrecord = record     w: word;     s: string;   end;    tmyrecordarray = array [1 .. 315] of tmyrecord;   tarraypointer = ^tmyrecordarray;  var pagebase: tarraypointer;  procedure ttestform.formcreate(sender: tobject); var   irecord: tmyrecord; begin   pagebase := allocmem(sizeof(tmyrecordarray));   irecord.w := 1;   irecord.s := 'test';   pagebase^[1] := irecord; end;  procedure ttestform.formdestroy(sender: tobject); begin   pagebase^[1] := default (tmyrecord);   freemem(tpagebase); end;

i'm sure i'm not doing right, suggestions appreciated.

the first thing code present works. finalizes , deallocate correctly without leaking. i'll try answer question more generally.

strings managed types , compiler needs use special memory allocation routines able manage them: new , dispose.

allocate with

new(pagebase);

and deallocate with:

dispose(pagebase);

the call new ensures members managed default initialized. , in other direction, dispose finalize managed members.

you manually code attempts. in real code need finalize every element of array. code finalizes one. of course, initializes 1 , written in question fine. perhaps short version question has simplified far fault has been removed.

however, not recommending deal managed types manually. use new , dispose that.

it's worth saying dynamic array simpler here. using dynamic array let compiler take care of allocation , deallocation, , handle managed types correctly.


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