System.GetMem Function

GetMem allocates a memory block.

Pascal

procedure GetMem(var P: Pointer; Size: Integer);

C++

GetMem(void * P, int Size);

File

System

Description

GetMem allocates a block of the given Size on the heap, and returns the address of this memory in parameter P. The bytes of the allocated buffer are not set to zero. To dispose of the buffer, use FreeMem. If there isn't enough memory available to allocate the block, an EOutOfMemory exception is raised.

Note: If the memory needs to be zero-initialized, use AllocMem instead.

Delphi Examples:

Copy Code

{
The following example opens a file of your choice and reads
the entire file into a dynamically allocated buffer. The
buffer and the size of the file are then passed to a routine
that processes the text, and finally the dynamically
allocated buffer is freed and the file is closed.
} 
procedure TForm1.Button1Click(Sender: TObject);
var
  F: file;
  Size: Integer;
  Buffer: PAnsiChar;
begin
  if OpenDialog1.Execute then
  begin
    AssignFile(F, OpenDialog1.FileName);
    Reset(F, 1);
    try
      Size := FileSize(F);
      GetMem(Buffer, Size);
      try
        BlockRead(F, Buffer^, Size);
        Memo1.Lines.Add(AnsiString(Buffer));
      finally
        FreeMem(Buffer);
      end;
    finally
      CloseFile(F);
    end;
  end;
end;