std::ignore for ignoring unused variable
<p>Is it a good approach to use <code>std::ignore</code> for ignoring unused variables?</p>

<p>Suppose I have a function like this:  </p>

<pre><code>void func(int i)
{
   //for some reason, I don't need i anymore but I cannot change signature of function    
   std::ignore = i; 
}
</code></pre>

<p><strong>Additional Info</strong></p>

<p>This was one example and some answers suggested to use <em>anonymous</em> variables. But how would I do it for other cases, like: </p>

<pre><code>int Thread_UnSafe_func_returnSomething():
void func()
{
   // To make it thread safe
   // Also it is required to call only once
   static int i = Thread_UnSafe_func_returnSomething();

   std::ignore = i;
}
</code></pre>