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This noncompliant code example declares the variable y as a static int. The value of test( x) is assigned to y within the test(int x) function. However, when test(int x) is called with an input which results in reaching the initialization of y more than once, such as the value 12, undefined behavior occurs. Note that this code does not present an infinite recursion and still causes the undefined behavior mentioned.

int test(int x){
  x--;
  if(x < 0 || x > 10)
  {
    return 0;
  }
  else
  {
    static int y = test(x);  //<--undefined behavior occurs here
    return y;
  }
}

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The behavior observed from running this code under various compilers differs.

In gcc3, this code will recurse as if y were a non-static variable.

In gcc4, upon reaching the initialization of y for the second time, the program will terminate with the following message:

terminate called after throwing an instance of
'__gnu_cxx::recursive_init'
  what():  N9__gnu_cxx14recursive_initE
Aborted (core dumped)

Compliant Solution (p with Block Scope)

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