请帮我看看这段代码，问题出在哪里：

import std.c.windows.windows;
import std.stream;
import std.string;

extern(Windows)
{
alias void function(in int,in char**) LPSERVICE_MAIN_FUNCTION;
struct _SERVICE_TABLE_ENTRY
{ 
char* lpServiceName;
LPSERVICE_MAIN_FUNCTION lpServiceProc;
}
alias _SERVICE_TABLE_ENTRY SERVICE_TABLE_ENTRY;
bool StartServiceCtrlDispatcherW(SERVICE_TABLE_ENTRY*);
alias StartServiceCtrlDispatcherW StartServiceCtrlDispatcher;

struct  _SERVICE_STATUS
{
   int  dwServiceType;
   int  dwCurrentState;
   int  dwControlsAccepted;
   int  dwWin32ExitCode;
   int  dwServiceSpecificExitCode;
   int  dwCheckPoint;
   int  dwWaitHint;
}
alias _SERVICE_STATUS SERVICE_STATUS;

alias void* SERVICE_STATUS_HANDLE;

enum:uint
{
SERVICE_WIN32_OWN_PROCESS = 0x00000010,
SERVICE_WIN32_SHARE_PROCESS = 0x00000020,
SERVICE_START_PENDING = 0x00000002,
SERVICE_ACCEPT_STOP = 0x00000001,
SERVICE_ACCEPT_SHUTDOWN = 0x00000004,
SERVICE_RUNNING = 0x00000004,
SERVICE_CONTROL_STOP = 0x00000001,
SERVICE_CONTROL_SHUTDOWN = 0x00000005,
SERVICE_STOPPED = 0x00000001,
SERVICE_WIN32 = (SERVICE_WIN32_OWN_PROCESS|SERVICE_WIN32_SHARE_PROCESS),
}

SERVICE_STATUS_HANDLE RegisterServiceCtrlHandlerW(char*,void function (int));
alias RegisterServiceCtrlHandlerW RegisterServiceCtrlHandler;

bool SetServiceStatus(SERVICE_STATUS_HANDLE,SERVICE_STATUS*);

void Sleep(int);

SERVICE_STATUS ServiceStatus;
SERVICE_STATUS_HANDLE hStatus;

void ServiceMain(int argc,char** argv)
{
ServiceStatus.dwServiceType = SERVICE_WIN32;
ServiceStatus.dwCurrentState = SERVICE_START_PENDING;
ServiceStatus.dwControlsAccepted = SERVICE_ACCEPT_STOP|SERVICE_ACCEPT_SHUTDOWN;
ServiceStatus.dwWin32ExitCode = 0;
ServiceStatus.dwServiceSpecificExitCode = 0;
ServiceStatus.dwCheckPoint = 0;
ServiceStatus.dwWaitHint = 0;
hStatus = RegisterServiceCtrlHandler("Service", &ControlHandler);
if (hStatus == null)
    {
return;
    }
ServiceStatus.dwCurrentState = SERVICE_RUNNING;
SetServiceStatus(hStatus, &ServiceStatus);
while (ServiceStatus.dwCurrentState == SERVICE_RUNNING)
{
if (My())
{
ServiceStatus.dwCurrentState = SERVICE_STOPPED;
ServiceStatus.dwWin32ExitCode  = -1;
SetServiceStatus(hStatus, &ServiceStatus);
return;
}
Sleep(SLEEP_TIME);
}
}

void ControlHandler(int request)
{
switch(request)
{
case SERVICE_CONTROL_STOP:
My();
ServiceStatus.dwWin32ExitCode = 0;
ServiceStatus.dwCurrentState = SERVICE_STOPPED;
SetServiceStatus (hStatus, &ServiceStatus);
return;
case SERVICE_CONTROL_SHUTDOWN:
My();
ServiceStatus.dwWin32ExitCode = 0;
ServiceStatus.dwCurrentState = SERVICE_STOPPED;
SetServiceStatus (hStatus, &ServiceStatus);
return;
default:
break;
} 
SetServiceStatus (hStatus, &ServiceStatus);
}
}


const int SLEEP_TIME=3000;
int main()
{
SERVICE_TABLE_ENTRY ServiceTable[2];
ServiceTable[0].lpServiceName ="Service";
    ServiceTable[0].lpServiceProc = &ServiceMain;
ServiceTable[1].lpServiceName = null;
    ServiceTable[1].lpServiceProc = null;
StartServiceCtrlDispatcher(&ServiceTable[0]);
return 0;
}

int tn=0;
int My()
{
File OutFile = new File;
try
{
tn++;
OutFile.open("f.txt", FileMode.Out);
OutFile.write(tn);
OutFile.close();
}
catch (Exception x)
{
return -1;
}
return 0;
}

这个服务可以注册和启动但是就是不能往f.txt里边写入内容，问题出在哪里呢?

知道f.txt在哪吗？

f.txt和程序在同一目录，我用控制台程序测试文件可以写入内容，服务就不能写入

谢谢楼上朋友的指点，问题解决了。内容没有写入本目录的f.txt而是在系统文件夹下新建了一个f.txt把内容写到那里边去了。