@tyler (void) tells gcc that the return value is intentionally being ignored and not to emit a warning.

Although in this case, getrandom() is not marked to warn if return ignored - but the (void) does signify that for the function there is a return value and it is intentionally being ignored (the getrandom syscall could possibly be interrupted by a signal and then there could be anything in selection (although in this case that doesn't matter, as a word repeated a few times is tolerated)).