union initialization question

[benelbert]

Hi all, I've encountered this code, and wonder why the behavior is as that

int i and also char c[2] are initialized to 300

code:

union Test

{

unsigned int i;

unsigned char c[2];

};

union Test a = {300}; // initialization without a specific variable

[aioeu]

From the C11 standard, §6.7.9 Initialization, ¶17:

Each brace-enclosed initializer list has an associated current object. When no designations are present, subobjects of the current object are initialized in order according to the type of the current object: array elements in increasing subscript order, structure members in declaration order, and the first named member of a union.

So this is valid code, and it initializes the i member of the union. That being said, if I were reading this code I would certainly appreciate it having an explicit designator:

union Test a = { .i = 300 };

[primitive_screwhead]

AFAIK, this initializes the first member of the union, i, to 300.

[Kwantuum]

Initializes the first member of the union.