LabVIEW
Unicode to UTF-8 conversion
Solved!
Actually ASCII is a VERY LIMITED subset of Unicode. And no, Unicode ist not UTF-16, but UTF-16 LE (little endian) is de Unicode version used on Windows. You also have UTF-8 and UTF-32 and for the 16 and 32 bit versions both an LE and BE version.
Windows NT uses internally everywhere UTF-16 LE, while translating it to 8-bit MBCS on demand for applications that don't use Unicode such as LabVIEW. And LabVIEW therefore does not really use ASCII but 8-bit MBCS. For most Windows codepages this means an extended ASCII code page with the lower 128 character codes mapped to the standard 7-bit ASCII characters and the upper 128 character points mapped to code page specific characters. But Asian and Arabian codepages can define more than 256 characters and then a single character suddenly consists of multiple bytes even in LabVIEW.
Linux uses nowadays internally mostly UTF-32 (LE or BE) depending on the endianess of the CPU but with most user systems nowadays running on x86/64 or ARM this is usually also LE.
On the user level it uses UTF-8 which is in fact also a MBCS encoding where a single character point can consist of 1 to 4 bytes. The first 128 characters in the ASCII table map exactly to the first 128 characters in the Unicode standard.
So if your LabVIEW was running on on a modern Linux system you theoretically would already use UTF-8 
On Windows to get to UTF-8 from UTF-16 LE one needs to simply call the function WideCharToMultyByte() with the first parameter set to CP_UTF8 (65001) instead of CP_ACP (0).
And be very careful to allocate a large enough buffer for the returned UTF-8 string. It can theoretically get up to 4 times as long in bytes as there are UTF-16 character points in the incoming string!
