I guess that Qt has functions to deal with W32-type registries.
Exehdr.exe from the toolkit lists with parameter /NO and the DLL pathname the exported funcs, among other outputs:
Exports:
ord obj offset name
22 1 00007840 RegOpenKeyA exported, shared data
11 1 0000754c RegEnumKeyA exported, shared data
25 1 00006a5c RegOpenKeyW exported, shared data
1 1 00006fb8 RegCloseKey exported, shared data
3 1 00007450 RegCreateKeyA exported, shared data
17 1 00006fa0 RegFlushKey exported, shared data
14 1 00006720 RegEnumKeyW exported, shared data
42 1 00007948 RegSetValueA exported, shared data
7 1 000074d0 RegDeleteKeyA exported, shared data
6 1 0000647c RegCreateKeyW exported, shared data
45 1 00006d0c RegSetValueW exported, shared data
8 1 000065d0 RegDeleteKeyW exported, shared data
23 1 000070dc RegOpenKeyExA exported, shared data
12 1 000075d0 RegEnumKeyExA exported, shared data
24 1 00005ea8 RegOpenKeyExW exported, shared data
13 1 00006848 RegEnumKeyExW exported, shared data
15 1 0000704c RegEnumValueA exported, shared data
16 1 00005d70 RegEnumValueW exported, shared data
30 1 000078c0 RegQueryValueA exported, shared data
43 1 000071e8 RegSetValueExA exported, shared data
33 1 00006bb0 RegQueryValueW exported, shared data
44 1 0000615c RegSetValueExW exported, shared data
9 1 00006fd0 RegDeleteValueA exported, shared data
4 1 00007394 RegCreateKeyExA exported, shared data
10 1 00005c20 RegDeleteValueW exported, shared data
5 1 000062f0 RegCreateKeyExW exported, shared data
26 1 00007a9c RegQueryInfoKeyA exported, shared data
31 1 0000715c RegQueryValueExA exported, shared data
27 1 00006e9c RegQueryInfoKeyW exported, shared data
32 1 00005ffc RegQueryValueExW exported, shared data
50 1 00004d74 KRegInit exported, shared data
51 1 000051c8 KRegTerm exported, shared data