Question

i.e., would the following be expected to execute correctly even in a multithreaded environment?

int dostuff(void) {
    static int somevalue = 12345;
    return somevalue;
}

Or is it possible for multiple threads to call this, and one call to return whatever garbage was at &somevalue before execution began?

Answer 1

From the C++ Standard, section 6.7:

A local object of POD type (3.9) with static storage duration
initialized with constant-expressions
is initialized before its block is
first entered.

This means that a function-level static object must be initialised by the first time the function is entered, not necessarily when the process as a whole is initialised. At this point, multiple threads may well be running.