From a cursory search I can't find any languages in the C standard that disallow reading not from the last written member. I'm familiar with such language in t

From a cursory search I can't find any languages in the C standard that disallow reading not from the last written member. I'm familiar with such language in the C++ standard. Edit: On the contrary, this note 92: > 92)If the member used to read the contents of a union object is not the same as the member last used to store a value in the object the appropriate part of the object representation of the value is reinterpreted as an object representation in the new type as described in 6.2.6 (a process sometimes called type punning). This can possibly be a non-value representation. Edit2: and that's specifically the text that was added by dr283. I think you might be confusing with a different DR (don't remember the number) that specifically asked if generalized type punning was possible as long as an union containing the aliased types was visible in the translation unit. I think that's still open although GCC definitely forbids it.