FPC3.0与InterlockedCompareExchange

Question

我安装了Lazarus1.6/FPC3.0，在Windows 10上安装了64位(64位)，并移植了包含InterlockedCompareExchangePointer功能的Delphi代码。

FPC3.0不包括InterlockedCompareExchangePointer声明；相反，它“重载”InterlockedCompareExchange (如systemh.inc中所示)

function InterlockedCompareExchange(var Target: longint; NewValue: longint; Comperand: longint): longint; public name 'FPC_INTERLOCKEDCOMPAREEXCHANGE';
{$ifdef cpu64}
function InterlockedCompareExchange64(var Target: int64; NewValue: int64; Comperand: int64): int64; public name 'FPC_INTERLOCKEDCOMPAREEXCHANGE64';
function InterlockedCompareExchange(var Target: Pointer; NewValue: Pointer; Comperand: Pointer): Pointer; external name 'FPC_INTERLOCKEDCOMPAREEXCHANGE64';
{$else cpu64}
function InterlockedCompareExchange(var Target: Pointer; NewValue: Pointer; Comperand: Pointer): Pointer; external name 'FPC_INTERLOCKEDCOMPAREEXCHANGE';
{$endif cpu64}

现在，我尝试在指针中使用InterlockedCompareExchange：

program Project1;

uses Windows;

function Test: Boolean;
var
  P1, P2: Pointer;

begin
  Result:= InterlockedCompareExchange(P1, P2, nil) <> nil
end;

begin
  Test;
end.

并且它不使用消息进行编译。

项目1.lpr(10，50)错误: arg no. 3的不兼容类型: Got“指针”，预期"LongInt“

因此，“超载”显然不起作用。怎么修呢？

我在默认(64位)目标上使用64位FPC3.0.

Answer 1

以下解决办法

{$ifdef fpc}
function InterlockedCompareExchangePointer(var Target: Pointer; NewValue: Pointer; Comperand: Pointer): Pointer;
begin
{$ifdef cpu64}
  Result:= Pointer(InterlockedCompareExchange64(int64(Target), int64(NewValue), int64(Comperand)));
{$else cpu64}
  Result:= Pointer(InterlockedCompareExchange(LongInt(Target), LongInt(NewValue), LongInt(Comperand)));
{$endif cpu64}
end;
{$endif fpc}

编译并确保Delphi/FPC的兼容性；看起来缺少InterlockedCompareExchangePointer声明是应该修复的FPC错误。

Answer 2

InterlockedCompareExchangePointer添加在FPC 3.1.1 (r34599)中：

http://bugs.freepascal.org/view.php?id=29965