How do you convert a wchar_t* returned by a C DLL to a String?

[ScottPJones]

@stevengj

By “this”, I guess you meant the utf16tostring method posted above. The transcode function, on the other hand, certainly handles non-BMP characters when translating between UTF-8 and UTF-16 in either direction.

Yes, I meant the original version in this post, which treated each 16-bit codepoint as if it were a character.

The final version with should be better, however, scanning first for a 16-bit 0, wrapping the pointed to words as a Vector, and then scanning the string yet again to calculate the length in UTF-8, before finally creating the String version will not be that efficient.

@stevengj

I agree that this should be built-into Base, however. In analogy with unsafe_string, maybe just an unsafe_transcode(String, p::Cwstring, length=wcslen(p)) method. LegacyStrings should be updated if needed, but it shouldn’t be needed just to convert data to/from String.

Yes, although I’d have separate methods instead of calling wcslen(p), to avoid scanning twice, and Cwstring can be 16-bit or 32-bit characters, depending on platform, so for UTF-16:
i.e. unsafe_transcode(String, p::Ptr{UInt16}) and unsafe_transcode(String, p::Ptr{UInt16}, len::Int)