Static Local Variable of a Template `inline` Function

Question

static local variables of an inline function in C++ are guaranteed to exist as if being a single global variable, if my understanding is correct.

Does the same apply if the inline function is a template, where the compiler can generate multiple versions of the function?

There is now way to have a global `inline` variable in multiple libraries (or a template `inline` variable in multiple translation units). There is no standardized linking. — , Jun 01 '15 at 19:36
@DieterLücking Do you mean that the `inline` variable proposal was accepted to be included in the next standard? — , Jun 01 '15 at 19:41
@DieterLücking You said "there is now way to have a **global inline variable** in multiple libraries". — , Jun 01 '15 at 19:46
A template function is not a function. It is a template for producing functions. Each set of template arguments (not function arguments) produces a distinct function. The rules around `inline` apply to each such function instance. Is that is what you are asking about? — Yakk - Adam Nevraumont, Jun 01 '15 at 20:32
@shuttle87 A static member is very different from a local static. — Alan Stokes, Jun 01 '15 at 21:26

score 5 · Accepted Answer · answered Jun 02 '15 at 11:46

In short: The Compiler produces one static variable for each template.

If you want to have the same variable for all templates you can maybe try something like this:

int& hack()
{
  static int i = 10;
  return i;
}

template <typename T>
void fun(const T& x)
{
  int &i = hack();
  cout << ++i;
  return;
}

1 Answers1