Recently I came across the following snippet, which is an attempt to ensure all bytes of i (nad no more) are accessible as individual elements of c:

union {
  int i;
  char c[sizeof(int)];
};

Now this seems a good idea, but I wonder if the standard allows for the case where the alignment requirements for char are more restrictive than that for int.

In other words, is it possible to have a four-byte int which is required to be aligned on a four-byte boundary with a one-byte char (it is one byte, by definition, see below) required to be aligned on a sixteen-byte boundary?

And would this stuff up the use of the union above?

Two things to note.

1. I'm talking specifically about what the standard allows here, not what a sane implementor/architecture would provide.

2. I'm using the term "byte" in the ISO C sense, where it's the width of a char, not necessarily 8 bits.