我正在编写一个程序,理想情况下它将在服务器上后台运行而不关闭 - 因此非常重要的一点是任何内存泄漏都不存在。我的程序涉及使用Windows终端服务API(wtsapi32.dll)检索实时会话信息,由于信息必须是实时的,因此该函数每隔几秒钟运行一次,我发现调用
总之:问题不在于执行
目前的短期解决方案是当使用的内存超过阈值时重新启动进程,但这似乎并不是一个令人满意的解决方案,纠正这个泄漏将是最理想的解决方案。
枚举类型直接取自Microsoft MSDN文档。
附上相关源文件。
WTSEnumerateSessionsEx
函数会导致相当大的内存泄漏。似乎根据MSDN文档中的指示调用WTSFreeMemoryEx
没有任何影响,但我对这两个调用都没有收到错误消息。总之:问题不在于执行
WTSEnumerateSessionsEx
,因为返回了有效数据;内存只是没有被释放,在长时间运行时会导致问题。目前的短期解决方案是当使用的内存超过阈值时重新启动进程,但这似乎并不是一个令人满意的解决方案,纠正这个泄漏将是最理想的解决方案。
枚举类型直接取自Microsoft MSDN文档。
附上相关源文件。
unit WtsAPI32;
interface
uses Windows, Classes, Dialogs, SysUtils, StrUtils;
const
WTS_CURRENT_SERVER_HANDLE = 0;
type
WTS_CONNECTSTATE_CLASS = (WTSActive, WTSConnected, WTSConnectQuery,
WTSShadow, WTSDisconnected, WTSIdle, WTSListen, WTSReset, WTSDown,
WTSInit);
type
WTS_TYPE_CLASS = (WTSTypeProcessInfoLevel0, WTSTypeProcessInfoLevel1,
WTSTypeSessionInfoLevel1);
type
WTS_SESSION_INFO_1 = record
ExecEnvId: DWord;
State: WTS_CONNECTSTATE_CLASS;
SessionId: DWord;
pSessionName: LPtStr;
pHostName: LPtStr;
pUserName: LPtStr;
pDomainName: LPtStr;
pFarmName: LPtStr;
end;
type
TSessionInfoEx = record
ExecEnvId: DWord;
State: WTS_CONNECTSTATE_CLASS;
SessionId: DWord;
pSessionName: string;
pHostName: string;
pUserName: string;
pDomainName: string;
pFarmName: string;
end;
TSessions = array of TSessionInfoEx;
function FreeMemoryEx(WTSTypeClass: WTS_TYPE_CLASS; pMemory: Pointer;
NumberOfEntries: Integer): BOOL; stdcall;
external 'wtsapi32.dll' name 'WTSFreeMemoryExW';
function FreeMemory(pMemory: Pointer): DWord; stdcall;
external 'wtsapi32.dll' name 'WTSFreeMemory';
function EnumerateSessionsEx(hServer: THandle; var pLevel: DWord;
Filter: DWord; var ppSessionInfo: Pointer; var pCount: DWord): BOOL;
stdcall; external 'wtsapi32.dll' name 'WTSEnumerateSessionsExW';
function EnumerateSessions(var Sessions: TSessions): Boolean;
implementation
function EnumerateSessions(var Sessions: TSessions): Boolean;
type
TSessionInfoExArr = array[0..2000 div SizeOf(WTS_SESSION_INFO_1)] of WTS_SESSION_INFO_1;
var
ppSessionInfo: Pointer;
pCount: DWord;
hServer: THandle;
level: DWord;
i: Integer;
ErrCode: Integer;
Return: DWord;
begin
pCount := 0;
level := 1;
hServer := WTS_CURRENT_SERVER_HANDLE;
ppSessionInfo := NIL;
if not EnumerateSessionsEx(hServer, level, 0, ppSessionInfo, pCount) then
begin
ErrCode := GetLastError;
ShowMessage('Error in EnumerateSessionsEx - Code: ' + IntToStr(ErrCode)
+ ' Message: ' + SysErrorMessage(ErrCode));
en
else
begin
SetLength(Sessions, pCount);
for i := 0 to pCount - 1 do
begin
Sessions[i].ExecEnvId := TSessionInfoExArr(ppSessionInfo^)[i].ExecEnvId;
Sessions[i].State := TSessionInfoExArr(ppSessionInfo^)[i].State;
Sessions[i].SessionId := TSessionInfoExArr(ppSessionInfo^)[i].SessionId;
Sessions[i].pSessionName := WideCharToString
(TSessionInfoExArr(ppSessionInfo^)[i].pSessionName);
Sessions[i].pHostName := WideCharToString
(TSessionInfoExArr(ppSessionInfo^)[i].pHostName);
Sessions[i].pUserName := WideCharToString
(TSessionInfoExArr(ppSessionInfo^)[i].pUserName);
Sessions[i].pDomainName := WideCharToString
(TSessionInfoExArr(ppSessionInfo^)[i].pDomainName);
Sessions[i].pFarmName := WideCharToString
(TSessionInfoExArr(ppSessionInfo^)[i].pFarmName);
end;
if not FreeBufferEx(WTSTypeSessionInfoLevel1, ppSessionInfo, pCount);
begin
ErrCode := GetLastError;
ShowMessage('Error in EnumerateSessionsEx - Code: ' + IntToStr(ErrCode)
+ ' Message: ' + SysErrorMessage(ErrCode));
end;
ppSessionInfo := nil;
end;
end;
end.
这里是一个最小化的 SSCCE 代码,演示了这个问题。当程序执行时,它很快地耗尽了可用内存。
program SO17839270;
{$APPTYPE CONSOLE}
uses
SysUtils, Windows;
const
WTS_CURRENT_SERVER_HANDLE = 0;
type
WTS_TYPE_CLASS = (WTSTypeProcessInfoLevel0, WTSTypeProcessInfoLevel1,
WTSTypeSessionInfoLevel1);
function WTSEnumerateSessionsEx(hServer: THandle; var pLevel: DWORD;
Filter: DWORD; var ppSessionInfo: Pointer; var pCount: DWORD): BOOL; stdcall;
external 'wtsapi32.dll' name 'WTSEnumerateSessionsExW';
function WTSFreeMemoryEx(WTSTypeClass: WTS_TYPE_CLASS; pMemory: Pointer;
NumberOfEntries: Integer): BOOL; stdcall;
external 'wtsapi32.dll' name 'WTSFreeMemoryExW';
procedure EnumerateSessionsEx;
var
ppSessionInfo: Pointer;
pCount: DWORD;
level: DWORD;
begin
level := 1;
if not WTSEnumerateSessionsEx(WTS_CURRENT_SERVER_HANDLE, level, 0,
ppSessionInfo, pCount) then
RaiseLastOSError;
if not WTSFreeMemoryEx(WTSTypeSessionInfoLevel1, ppSessionInfo, pCount) then
RaiseLastOSError;
end;
begin
while True do
EnumerateSessionsEx;
end.
WTSEnumerateSessions
似乎没有任何问题。我不知道你是否可以使用它。 - David Heffernan