This is categorically incorrect. The documentation for the function is entirely accurate. What is true is that the regedit program is more than a featureless wrapper around the API functions (unlike the first thing to know about Linux desktop software). The heuristic is performed for the user who probably doesn't know what they want; the straight exactly-as-you-asked-for-it conversion is performed for the programmer who does. (And it's only a heuristic for values; the encoding for keys is assumed from the file like TFA says, but which one it is is stored in a flag bit.)