Hello
I'm passing a dynamic array to a WinAPI function - each array element is a record with two fields - the first field is an Integer,
the second is a PWideChar. Separately I have an array of Strings, I size my dynamic array to match the length of the String array,
then I copy each String into a PWideChar field, as below (I've changed the array names to make this clearer - hopefully):
var
Lo, Hi, i, LenW: Integer;
...
Lo := Low(StringArray);
Hi := High(StringArray);
// Set the dynamic array length to match the String array length
SetLength(Int_PWideChar_Array, Length(StringArray));
for i := Lo to Hi do begin
Int_PWideChar_Array[i].IntegerField := SomeNumber;
// Get the length of the String array element, then double for equiv WideString + 1 for #0
WLen := Length(StringArray[i]) * 2 + 1;
// Allocate memory for the PWideChar
Int_PWideChar_Array[i].pszText := AllocMem(WLen);
StringToWideChar(StringArray[i], Int_PWideChar_Array[i].pszText, WLen);
end;
This works as expected, and the WinAPI function call operates correctly. I've seen various messages that suggest you can do things
like:
for i := Lo to Hi do begin
Int_PWideChar_Array[i].IntegerField := SomeNumber;
Int_PWideChar_Array[i].pszText := PWideChar(WideString(StringArray[i]));
end;
...but that seems to produce odd results (the first Int_PWideChar_Array element 'pszText' value always seems to get overwritten with
the last). My question, then, is - since I use AllocMem, shouldn't I need to call FreeMem/Dispose?
I only ask because at the moment I don't, and FastMM doesn't mention any leaks. If I add FreeMem or Dispose after the WinAPI call
has completed, FastMM complains about corrupted memory:
for i := Lo to Hi do
Dispose(Int_PWideChar_Array[i].pszText);
I'd be very grateful if someone could clarify this for me - many thanks in advance.
