Are inline variables unique across boundaries? : <p>This is a follow up of <a href="https://stackoverflow.com/questions/51332851/alternative-id-generators-for-types/51334917#comment89715080_51334917">this question</a>.<br>
As mentioned in the comments to the answer:</p>

<blockquote>
  <p>An inline variable has the property that - <em>It has the same address in every translation unit</em>. [...] Usually you achieved that by defining the variable in a cpp file, but with the inline specifier you can just declare/define your variables in a header file and every translation unit using this inline variable uses exactly the same object.</p>
</blockquote>

<p>Moreover, from the answer itself:</p>

<blockquote>
  <p>While the language does not guarantee (or even mention) what happens when you use this new feature across shared libraries boundaries, it does work on my machine.</p>
</blockquote>

<p>In other terms, it isn't clear if an inline variable is guaranteed to be unique across boundaries when shared libraries are involved. Someone proved empirically that <em>it works</em> on some platforms, but it isn't properly an answer and it could just break everything on other platforms.</p>

<p>Is there any guarantee regarding the uniqueness of an inline variable when it is used across boundaries or is it simply an implementation detail that I should not rely on?</p>
