[lazarus] mwEdit Problems

[Michael A. Hess]

Shane Miller wrote:
> 
> Why do I need the current size?  I should be able to do a
> sizeof(pointer) to get the size.

That will give you the size of a pointer. Not the size of the area the
pointer is pointing to.  :-\

Unless you use the memory manager found in Delphi 2 and up your have
know way of knowning how much memory is associated with a pointer to a
memory location. You have to tell it how much memory it is associated
with.

> Actually I don't need to do that because if I am REALLOCating
> memory, all I need to do is a freemem(pointer) getmem(pointer,newsize)

This is how the current ReAllocMem works and what can be passed to it.
As I said this is a direct match to Delphi 1.

1. if P is nil and newSize is zero do nothing
2. if P is nil and newSize is NOT zero allocate memory and clear it to 0
3. if P is NOT nil and newSize is NOT zero a new memory block allocated
   the data is copied from the old block to the new block and the old
   block is disposed of.

if P is NOT nil then currentSize must be the size used to allocate
memory for P whether it was using AllocMem or ReAllocMem.

procedure ReAllocMem(var P: Pointer; currentSize: longint; newSize:
longint);


> Can we get another reallocmem function added to the rtl?

Unless a memory management scheme is used for AllocMem and ReAllocMem
that will maintain a record of allocated space for memory blocks when
using these routines you will have to pass the current size of the
existing allocated memory.

Since ReAllocMem was written I have seen some notes that indicate that
Peter might have added some heap management that will allow you to do a
freemem(pointer) without suppling the size of the memory block. If that
is the case we can of course change ReAllocMem to use this form of
FreeMem and hopefully be able to identify the size of the block for the
copy block function.

Peter is that the case????



-- 
==== Programming my first best destiny! ====

Michael A. Hess      Miracle Concepts, Inc.
mhess at miraclec.com   http://www.miraclec.com