>>260
はいはい。「MSが始めたソレ」ね。ツツシンデ訂正します。

>>262
無駄な努力続けたいならどーぞ。visual studio 6.0(1998)

https://msdn.microsoft.com/en-us/library/aa243791(v=vs.60).aspx
Microsoft Specific —>
Nested unions can be declared anonymously when they are members of another structure or union. This is an example of a nameless union:
struct str
{
int a, b;
union / * Unnamed union */