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    <blockquote> <p>Within the same compilation unit, the C++ standard says that static initialization order is well defined -- it's the order of the declarations of the static objects.</p> </blockquote> <p>In your shown code you have no declaration of a static data member. You have a declaration of a typedef-name. These have nothing to do with that, and don't influence any order. <em>You probably think along this way</em>:</p> <blockquote> <p>If i make that typedef declaration, it will instantiate <code>helper&lt;int&gt;</code>, and thus instantiate its static data member declaration first.</p> </blockquote> <p>The problem is, that line does not cause an instantiation of <code>helper&lt;int&gt;</code>. For that to happen, you would need an explicit instantiation or manage to make it instantiate it implicitly (creating an object of <code>helper&lt;int&gt;</code> for example, or using it as a nested name specifier as in <code>helper&lt;int&gt;::...</code> and explicitly referencing the static member - otherwise, creation of it is omitted). </p> <p>But there is a much deeper problem. The order is <em>not</em> the declaration of the static data-members. The order is <em>their definition</em>. Consider the following</p> <pre><code>struct C { C() { printf("hey\n"); } }; struct A { static C a; static C b; }; C A::b; C A::a; </code></pre> <p>In this code, <strong>b is created before a</strong>, even though <strong>a is declared before b</strong>. </p> <p>The following code prints <code>2 1</code>:</p> <pre><code>struct C { C(int n) { printf("%d\n", n); } }; template&lt;int N&gt; struct A { static C c; }; template&lt;int N&gt; C A&lt;N&gt;::c(N); // explicit instantiation of declaration and definition template struct A&lt;2&gt;; template struct A&lt;1&gt;; int main() { } </code></pre> <p>But the following code prints nothing, unless you comment in the line in <code>main</code>.</p> <pre><code>struct C { C(int n) { printf("%d\n", n); } }; template&lt;int N&gt; struct A { static C c; }; template&lt;int N&gt; C A&lt;N&gt;::c(N); // implicit instantiation of declarations A&lt;2&gt; a2; A&lt;1&gt; a1; int main() { // A&lt;1&gt;::c; A&lt;2&gt;::c; } </code></pre> <p>I'm not actually sure what the correct output for this second snippet is. Reading the Standard, i can't determine an order. It says at <code>14.6.4.1</code> "Point of Instantiation":</p> <blockquote> <p>For a function template specialization, a member function template specialization, or a specialization for a member function or static data member of a class template, if the specialization is implicitly instantiated because it is referenced from within another template specialization [...]. Otherwise, the point of instantiation for such a specialization immediately follows the namespace scope declaration or definition that refers to the specialization.</p> </blockquote> <p>The point of instantiation of their definitions both appear immediately after the definition of <code>main</code>. Which definition is instantiated before the other definition seems to be left unspecified. If anyone knows the answer and khow other compilers behave (GCC prints <code>1 2</code> but with the order of the expressions in <code>main</code> swapped, prints <code>2 1</code>), please let me know in the comment.</p> <p>For details, see <a href="https://stackoverflow.com/questions/1079623/what-is-the-lifetime-of-class-static-variables-in-c/1080211#1080211">this answer about static object's lifetime</a>.</p>
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    1. USJohannes Schaub - litb
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    1. COThanks for the thorough, informative answer.
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      1. USDrew Hoskins
    2. COUnfortunately, if your answer is correct and I understand you correctly, then I think the Sun compiler is still wrong. In the code following the original snippet, s1::something_using_the_static_member was used before s0::something_using_the_static_member. I switched the order, but Sun still constructs s1's static member before s0's. Is my thinking correct?
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    3. COSee my edit of original post
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