[fpc-pascal]Pointer Help

[James Mills]

On Sun, Feb 09, 2003 at 03:42:29PM +0100, Anton Tichawa wrote:
> Hi,
> 
> > But getMem and reAllocMem allocate a number of bytes on the heap,
> > wouldn't you have to free that number of bytes using freeMem(pointer, n)
> > ?
> 
> No, Free Pascal keeps track of the allocated size for a pointer created with 
> GetMem/ReallocMem. They need this information for heap management, so it's a 
> good think to use this information to save one procedure parameter, which is 
> a lot. If you want to determine the number of bytes to deallocate, you may do 
> this by using:
> 
>   Function FreeMemSize(var p:pointer;Size:Longint):Longint;
> 
> Definition:
> FreememSize
> This function should release the memory pointed to by P. The argument Size is 
> the expected size of the memory block pointed to by P. This should be 
> disregarded, but can be used to check the behaviour of the program. 
> 
> I think with FreeMemSize you may corrput the heap, so be careful with it!
> 
> Anton.

Ok thank you very muchly :) You've been a great help.

> 
> 
> >
> > Btw, I'm using short strings, so I think it'll be ok for now...
> >
> > > Read the Manual - Free Pascal Programmer's Manual, Section 4.5, "Writing
> > > Your Own Memory Manager" - because that's what you're actually doing.
> > >
> > > HTH
> > >
> > > Anton Tichawa.
> > >
> > >
> > >
> > > ----------
> > >
> > > "Adas Methode war, wie sich zeigen wird, Tagtr?ume in offenbar korrekte
> > > Berechnungen einzuweben."
> > >
> > > Doris Langley Moore: Ada, Countess of Lovelace (London 1977).
> > >
> > > ----------
> > >
> > > Anton Tichawa
> > > Volkertstrasse 19 / 20
> > > A-1020 Wien
> > > mobil: +43 664 52 07 907
> > > email: anton.tichawa at chello.at
> > >
> > > ----------
> > > _______________________________________________
> > > fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
> > > http://lists.freepascal.org/mailman/listinfo/fpc-pascal
> >
> > _______________________________________________
> > fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
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> 
> -- 
> 
> ----------
> 
> "Adas Methode war, wie sich zeigen wird, Tagtr?ume in offenbar korrekte 
> Berechnungen einzuweben."
> 
> Doris Langley Moore: Ada, Countess of Lovelace (London 1977).
> 
> ----------
> 
> Anton Tichawa
> Volkertstrasse 19 / 20
> A-1020 Wien
> mobil: +43 664 52 07 907
> email: anton.tichawa at chello.at
> 
> ----------
> _______________________________________________
> fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
> http://lists.freepascal.org/mailman/listinfo/fpc-pascal