1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:
43:
44:
45:
46:
47:
48:

unit SRWLock;

interface

type
  // The slim reader/writer (SRW) lock enables the threads of a single process to access shared resources. 
  // It is optimized for speed and occupies very little memory.
  TSRWLock = class
  private
    FLock: Pointer;
  public
    procedure AcquireShared;
    procedure ReleaseShared;
    procedure AcquireExclusive;
    procedure ReleaseExclusive;
  end;

implementation

procedure AcquireSRWLockShared(var P: Pointer); stdcall; external 'kernel32.dll' name 'AcquireSRWLockShared';
procedure ReleaseSRWLockShared(var P: Pointer); stdcall; external 'kernel32.dll' name 'ReleaseSRWLockShared';

procedure AcquireSRWLockExclusive(var P: Pointer); stdcall; external 'kernel32.dll' name 'AcquireSRWLockExclusive';
procedure ReleaseSRWLockExclusive(var P: Pointer); stdcall; external 'kernel32.dll' name 'ReleaseSRWLockExclusive';

{ TSRWLock }

procedure TSRWLock.AcquireShared;
begin
  AcquireSRWLockShared(FLock);
end;

procedure TSRWLock.ReleaseShared;
begin
  ReleaseSRWLockShared(FLock);
end;

procedure TSRWLock.AcquireExclusive;
begin
  AcquireSRWLockExclusive(FLock);
end;

procedure TSRWLock.ReleaseExclusive;
begin
  ReleaseSRWLockExclusive(FLock);
end;

end.