Is a bad practice to declare static variables into functions/member functions?

Question

Recently a fellow worker showed to me a code like this:

void SomeClass::function()
{
    static bool init = false;

    if (!init)
    {
        // hundreds          


        

Answer 1

Global state is probably the worst problem here. Other functions don't have to be concerned with it, so it's not an issue. The fact that it can be achieved without static variable essentially means you made some form of a singleton. Which of course introduces all problems that singleton has, like being totally unsuitable for multithreaded environment, for one.