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Comment by pjmlp | Hacker News Reader

Now try that with other C compilers as well, or without using static.

Also add common C extensions into the soup like constructor function attributes.

Finally ISO/IEC 9899:2011, section 5.1.2.

"All objects with static storage duration shall be initialized (set to their initial values) before program startup. The manner and timing of such initialization are otherwise unspecified. Program termination returns control to the execution environment."

Don't mix what your compiler does, with what the standard requires.

Doing so only leads to unportable programs and misunderstandings.

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The C11 standard is clear here on syntax for a static initializer.

Read section 6.7.9, constraint 4:

  All the expressions in an initializer for an object that
  has static or thread storage duration shall be constant 
  expressions or string literals.

It's syntax, not initialization.

And that makes sense. However the memory is initialized before runtime could be via memcpy() it could be loaded as part of the executable and then mapped dynamically at runtime. That's what 5.1.2 is saying.

What 6.7.9 constraint 4 is saying, is that static variables can only be constant expressions.

Yes, but global variables are not necessarily static.

I think you're missing the point entirely here.

C++ has to run code before main if a ctor is in a class that's static. There's no other way to initialize that static object.

C prevents this by requiring static storage to be initialized with constants.

Fair enough.

All variables declared at file scope have static storage duration in C.

I was talking about using static keyword.

Yes, but what's important here is the storage duration, which the static keyword doesn't affect at file scope (it just affects the symbol scope).

Use of static in the context of that C snippet is deprecated in C++. One is supposed to use an unnamed namespace instead.

    namespace {
        int myfunc() {
            return 5;
        }
    
        int x;
        int y = 4;
        int z = myfunc();
     };

     int main()
     {}

In my opinion, his point is still valid.

Just FYI, I believe that deprecated usage was later undeprecated. See https://stackoverflow.com/questions/4726570/deprecation-of-t...

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