?

I think it can be implemented easily using

InterlockedCompareExchange,

no?

Yes it will be but to my knowledge there exists no platform independent version of InterlockedCompareExchange in Free Pascal...and even none for 64Bit.

For a new memory manager there must be a lowlevel function supporting this.
Also this operation must not be reordered/optimized by the compiler.

The operation should preferrably be a
InterlockedCompareExchangePointer()
wich always does the right thing :-) depending on architecture ...

For the interested ...

http://en.wikipedia.org/wiki/Compare-and-swap

http://groups.google.de/group/comp.programming.threads/browse_frm/thread /d062e1bfa460a375/3461ab7dd927a6ec?group=comp.programming.threads#3461ab 7dd927a6ec

helmut

It's in the interface of the system unit for 2.1.1

Jonas

That's true.

Well, at least on sparc it uses a hidden global lock, so there it's pretty useless :)

Maybe you should first in the RTL code before writing something, from systemh.inc:

function InterLockedIncrement (var Target: longint) : longint; public
name 'FPC_INTERLOCKEDINCREMENT';
function InterLockedDecrement (var Target: longint) : longint; public
name 'FPC_INTERLOCKEDDECREMENT';
function InterLockedExchange (var Target: longint;Source : longint) :
longint; public name 'FPC_INTERLOCKEDEXCHANGE';
function InterLockedExchangeAdd (var Target: longint;Source :
longint) : longint; public name 'FPC_INTERLOCKEDEXCHANGEADD';
function InterlockedCompareExchange(var Target: longint; NewValue:
longint; Comperand: longint): longint; public name
'FPC_INTERLOCKEDCOMPAREEXCHANGE';
{$ifdef cpu64}
function InterLockedIncrement64 (var Target: int64) : int64; public
name 'FPC_INTERLOCKEDINCREMENT64';
function InterLockedDecrement64 (var Target: int64) : int64; public
name 'FPC_INTERLOCKEDDECREMENT64';
function InterLockedExchange64 (var Target: int64;Source : int64) :
int64; public name 'FPC_INTERLOCKEDEXCHANGE64';
function InterLockedExchangeAdd64 (var Target: int64;Source : int64)
: int64; public name 'FPC_INTERLOCKEDEXCHANGEADD64';
function InterlockedCompareExchange64(var Target: int64; NewValue:
int64; Comperand: int64): int64; public name
'FPC_INTERLOCKEDCOMPAREEXCHANGE64';
{$endif cpu64}
{ Pointer overloads }
{$ifdef cpu64}
function InterLockedIncrement (var Target: Pointer) : Pointer;
external name 'FPC_INTERLOCKEDINCREMENT64';
function InterLockedDecrement (var Target: Pointer) : Pointer;
external name 'FPC_INTERLOCKEDDECREMENT64';
function InterLockedExchange (var Target: Pointer;Source : Pointer) :
Pointer; external name 'FPC_INTERLOCKEDEXCHANGE64';
function InterLockedExchangeAdd (var Target: Pointer;Source :
Pointer) : Pointer; external name 'FPC_INTERLOCKEDEXCHANGEADD64';
function InterlockedCompareExchange(var Target: Pointer; NewValue:
Pointer; Comperand: Pointer): Pointer; external name
'FPC_INTERLOCKEDCOMPAREEXCHANGE64';
{$else cpu64}
function InterLockedIncrement (var Target: Pointer) : Pointer;
external name 'FPC_INTERLOCKEDINCREMENT';
function InterLockedDecrement (var Target: Pointer) : Pointer;
external name 'FPC_INTERLOCKEDDECREMENT';
function InterLockedExchange (var Target: Pointer;Source : Pointer) :
Pointer; external name 'FPC_INTERLOCKEDEXCHANGE';
function InterLockedExchangeAdd (var Target: Pointer;Source :
Pointer) : Pointer; external name 'FPC_INTERLOCKEDEXCHANGEADD';
function InterlockedCompareExchange(var Target: Pointer; NewValue:
Pointer; Comperand: Pointer): Pointer; external name
'FPC_INTERLOCKEDCOMPAREEXCHANGE';
{$endif cpu64}

Peter