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Unicode version of CreateDirectory() API

Posted on 2004-04-22
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Last Modified: 2013-12-03
When I call CreateDirectory("c:\\"invalid name"\tmp") ) Win32 API it returns FALSE and GetLastError() returns a valid error code (incorrect syntax). Now, if I call unicode version of CreateDirectoryW() GetLastError() does not report any error. How can I check the error of unicode CreateDirectoryW()?
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Question by:alex1234
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Expert Comment

by:_corey_
ID: 10892073
CreateDirectoryW is failing, correct?
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Author Comment

by:alex1234
ID: 10892161
Yes, it returns FALSE and, according to API documentation, GetLastError() should return error code and it didn't for CreateDirectoryW().

I call CreateDirectoryW() by loading kernel32.dll dynamically and explicitly calling CreateDirectoryW(). Calling CreateDirectoryA() from the same dynamically loaded kernel32.dll causes GetLastError() return correct error code
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by:_corey_
ID: 10892258
Is there any particular reason you don't just call CreateDirectoryW explicitely from the code?
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Author Comment

by:alex1234
ID: 10892364
I just called CreateDirectoryW() directly - same result
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by:Anthony2000
ID: 10908399
Can you post your code snippet?
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Author Comment

by:alex1234
ID: 10918008
The code (two tests under Windows2000):

1)

if ( ! CreateDirectory("c:\\\"invalid name\"\\Tmp") )
{
DWORD err = GetLastError();
}

In this case err == some error code (incorrect syntax, I don't remember the code value now)

1)

if ( ! CreateDirectoryW("c:\\\"invalid name\"\\Tmp") )
{
DWORD err = GetLastError();
}

In this case err == 0 and directory was not created
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Expert Comment

by:Madshi
ID: 10918349
Don't you need to put a "L" before C++ wide strings?

L"blabla"
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Author Comment

by:alex1234
ID: 10918748
Madshi, you've just directed me to resolving the issue! The exact code thet didn't work was:

CreateDirectoryW(_bstr_t("\\\\?\\c:\\\"invalidname\""), NULL );

I've tried this and it worked:

CreateDirectoryW(L"\\\\?\\c:\\\"invalidname\"", NULL );

So, the problem was _bstr_t, somehow CreateDirectoryW() does not report errors when _bstr_t is used. I still don't understand why??



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Accepted Solution

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Madshi earned 125 total points
ID: 10918773
Actually I'm a Delphi programmer, so it's hard for me to tell. But in Delphi if I use automated wide string support, the GetLastError value might be destroyed, too. Is that _bstr_t something like automated wide string support? In that case please try to understand what the compiler makes out of your code! It will first have to convert the ansi string to wide, then it will call CreateDirectoryW with the converted string, then it will free the converted string. Only THEN you ask GetLastError. I think freeing a wide string destroys the GetLastError value. Do you see the problem?

But as I said, I'm only guessing here...
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Expert Comment

by:_corey_
ID: 10918856
The SysFreeString in _bstr_t might be the culprit, but hard to tell since the function doesn't say it will use error values.

Definately something coming off the stack is killing the error values.
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Author Comment

by:alex1234
ID: 10918867
Madshi,

it looks like you are 100% right! This code works:

_bstr_t str("\\\\?\\c:\\\"invalidname\"");
if ( ! CreateDirectoryW((LPCWSTR)(wchar_t*)str, NULL ) )
{
DWORD err = GetLastError();
}

Thanks!!!
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