调用SHGetSpecialFolderLocation（）函数时，系统帐户和管理员帐户有什么区别？

Question

I write two program, one is windows service run in system account(named xxService) and the other one is common application run in Administrator account(named xx);

They use the same code to get CSIDL_COMMON_DOCUMENTS directory. In most machine , they run well.

But some machine, the xxService can get the correct directory, the xx have failure in SHGetSpecialFolderLocation() ;

edit: the program only run on Windows XP(sp3).

edit2: Use SHGetFolderPathA() function to solve this problem.

My english is poor, everybody excuse me!

log:

[2964] [db](tid=1108)(pid=2964): SHGetSpecialFolderLocation() fail.hr=0x80070057, ierr=122

the detail error info:

//
// MessageId: E_INVALIDARG
//
// MessageText:
//
// One or more arguments are invalid
//
#define E_INVALIDARG _HRESULT_TYPEDEF_(0x80070057L)

ERROR_INSUFFICIENT_BUFFER
122 (0x7A)
The data area passed to a system call is too small.

code:

 //C:\Users\Public\Documents
 LPITEMIDLIST pidl;
 LPMALLOC pShellMalloc;
 HRESULT hr = S_FALSE;
 hr = SHGetMalloc(&pShellMalloc);
 if(SUCCEEDED(hr))
 {
     hr = SHGetSpecialFolderLocation(NULL,CSIDL_COMMON_DOCUMENTS,&pidl);
     if(SUCCEEDED(hr))
     {
         if(!SHGetPathFromIDListW(pidl, strDbFilePath))
         {
             int ierr=GetLastError();
             DebugMsgW((L"SHGetPathFromIDListW() fail., ierr=%d"), ierr);
         }
         DebugMsgW(L"DBpath=%s",strDbFilePath);
         pShellMalloc->Free(pidl);
     }
     else
     {
         int ierr=GetLastError();
         DebugMsgW((L"SHGetSpecialFolderLocation() fail.hr=0x%x, ierr=%d"), hr, ierr);
     }
     pShellMalloc->Release();
 }
 else
 {
     int ierr=GetLastError();
     DebugMsgW((L"SHGetMalloc() fail.hr=0x%x, ierr=%d"), hr, ierr);
 }

Answer 1

SHGetSpecialFolderLocation() (and any other function that returns an HRESULT) does not use GetLastError() to report error codes, since the HRESULT is the error code. Even SHGetPathFromIDList() is not documented as using GetLastError() , either. So the return value of GetLastError() is irrelevant in your example and needs to be removed to avoid confusion.

As for the E_INVALIDARG error, you are using a legacy function. CSIDL_COMMON_DOCUMENTS is known to fail in SHGetSpecialFolderLocation() on some systems. You need to use a newer function, such as SHGetFolderPath() , or SHGetKnownFolderPath() on Vista+.