CODEWITHSUNDEEP
c++winapiunicodec++11
D.R.
D.R.

Reputation: 21194

WinAPI LPWSTR, C++11 u16string?

If I'm developing for Windows and some WinAPI functions require me to use LPWSTR as string data type. Is it okay to use C++11's u16string in my library? Are those two data types the same thing?

It looks more like LPWSTR is wchar_t, but nobody likes wchar_t anymore...

Upvotes: 4

Views: 2551

Answers (3)

ecatmur
ecatmur

Reputation: 157324

wchar_t and char16_t are distinct types, so it is not possible to use u16string.c_str() as a LPWSTR (without a reinterpret_cast that would cause undefined behavior).

If you are confident that on your platform wchar_t is encoded as UTF-16, you can copy the data across:

std::wstring my_wstring(my_u16string.begin(), my_u16string.end());

and then use my_wstring.c_str() as LPWSTR. In a function call, you can use a temporary:

SomeWindowsAPI(std::wstring(my_u16string.begin(), my_u16string.end()).c_str());

Upvotes: 2

Remy Lebeau
Remy Lebeau

Reputation: 595762

wchar_t on Windows is 16-bit, and LPWSTR values are UTF-16 encoded, so yes, you can use char16_t and u16string values when interacting with the API, though you will have to typecast to keep the compiler happy.

Upvotes: 1

Cheers and hth. - Alf
Cheers and hth. - Alf

Reputation: 145239

The C++11 char16_t type is distinct from wchar_t. In theory you could reinterpret_cast your way between char16_t* and Windows’ wchar_t* (Windows’ wchar_t is 16 bits). In practice, however, Visual C++ 10.0 – and I think also Visual C++ 11.0 – lacks support for Unicode literals like u'A' or u"A".

Summing up (I’ve found that on SO one should better make all conclusions explicit):

  • “Is it okay to use C++11's u16string in my library?”
    Certainly, but not as direct plug-in replacements for wchar_t strings, and as of 2012 currently problematic (due to lack of support for literals) if you plan on supporting Visual C++.

  • “Are those two data types the same thing?”
    No.

  • “nobody likes wchar_t anymore...”
    That’s certainly not the case.

Upvotes: 2

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