you do have to cast it, though: `foo((vec2){.x=2, .y=2})`

the oldest MSVC on godbolt also accepts it, so it should be very portable as long as you're not using some embedded compiler from the mid 90s

a related fun thing is that you can pass it by pointer, and the lifetime will extend until the function is done:

`foo(&(vec2){ .x=2, .y=2 })`

> 6. The value of the compound literal is that of an unnamed object initialized by the initializer list. If the compound literal occurs outside the body of a function, the object has static storage duration; otherwise, it has automatic storage duration associated with the enclosing block.

it's valid until the end of the block. so, if the function returns the pointer, you can even use that until the end of the block

there's actually an example in the spec, on that page:

> drawline(&(struct point){.x=1, .y=1}, &(struct point){.x=3, .y=4});