[SOLVED] TMemoryStream Question with possible bug FPC 3.2.2

[Schmitty2005]

TMemoryStream  is backed only by a single block of memory (accessible via the aptly named  Memory  property), meaning that you can just call  FillChar / FillQWord / ZeroMemory  et al. on that block. You don't even need to reset the position since  Memory  always refers to the start of the block:

Code: Pascal  [Select][+][-]

1. procedure ZeroStream(Stream: TMemoryStream);
2. begin
3.   FillChar(Stream.Memory^, Stream.Size, 0);
4. end;

FillChar is exactly the one-liner I was looking for !  Thank you!

P.S.: You don't need to pass class instances as  var  in most cases; even with  const  class members may still be modified.
Class instances are essentially pointers, and class types don't get special treatment for  var / out / const / constref;  these specifiers still refer to the pointer value of a class instance and not the instance data.
Just FYI 

I am a novice, thank you for pointing that out as well.

[Schmitty2005]

In such a case I'd probably just use a TBytesStream (one of TMemoryStream descendants), built from a dynamic array. Dynamic arrays (as far as I remember), are guaranteed to be zero-initialized from the compiler. Like this:

Code: Pascal  [Select][+][-]

1. function CreateStream: TBytesStream;
2. var
3.   Buffer: array of Byte;
4. const
5.   Samples = 44100 * 2 * 10; { 10 secs at 44khz 16-bit stereo }
6.   SizeInBytes = Samples * 2;
7. begin
8.   SetLength(Buffer, SizeInBytes);
9.   Result := TBytesStream.Create(Buffer);
10. end;

I will do this in the future, as it seems to make more sense than what I was doing.  Thank you!