I think that unions can be perfect for what i have in mind and especially when I consider that my code should run on a really heterogeneous family of machines, especially low-powered machine, what is bugging me is the fact that the people who creates compilers doesn't seem to care too much about introducing and offering a good union support, for example this table is practical empty when it comes to Unrestricted Unions support, and this is a real unpleasant view for my projects.
There are alternatives to union that can at least mimic the same properties ?
Union is well supported on most compilers, what's not well supported are unions that contains members that have non trivial constructor (unrestricted unions). In practice, you'd almost always want a custom constructor when creating unions, so not having unrestricted union is more of a matter of inconvenience.
Alternatively, you can always use void pointer pointing to a malloc-ed memory with sufficient size for the largest member. The drawback is you'd need explicit type casting.
