判断文件是否被占用

判断文件FileName是否正在被打开/使用，如果被占用返回true，否则返回false

function IsFileInUse(const FileName: string): boolean;

var

HFileRes: HFILE;

begin

if not FileExists(FileName) then

begin

Result := False;

Exit;

end;

try

HFileRes := CreateFile(pchar(FileName), GENERIC_READ,

0 {this is the trick!}, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);

Result := (HFileRes = INVALID_HANDLE_VALUE);

if not Result then

CloseHandle(HFileRes);

except

Result := true;

end;

end;