riched20: EM_GETLINE implementation and test

[Andrew Talbot]

James Hawkins wrote:
> To be as portable as possible, we code to the lowest common
> denominator.  Not all compilers support L"".  We adhere to C89, but I
> can't remember what it says about L"", if anything.  The point is that
> WCHAR blah[] ={...} will work for every compiler.
> 

>From what I can tell, L"" is good in C89 (although the result of
concatenating a wide string and a narrow string is undefined). However, the
width of wchar_t is implementation-dependent, and may have a width anywhere
between that of char and unsigned long (though, in practice, it is likely
to be a synonym for an integer type that has at least a 16-bit
representation, such as short or unsigned short). Whereas WCHAR is set to
have a width of sixteen bits. So I think this is why the L-prefix form is
not portable.

Thanks for helping me down this road of discovery.

-- Andy.