Question

I have a C++ program which forks child processes to do some work. In these child processes some classes are created and there is a static variable inside a member function like so:

void MyClass::foo () {
    static std::string uuid;
    ...
    uuid = "A new value";
}

Since each process is freshly forked, I assumed uuid to always be initialized as an empty string. However, in some cases I noticed the uuid already has been given a value upon the first entry of the function, which causes problems.

How can this static variable be initialized across forked processes? And is my only option to use an class variable? The reason for the static variable is that I didn’t want to introduce class variables which are only used inside a single function so to keep the class nice and tidy.

Answer 1

I found out MyClass is also instantiated in the parent process in rare situations. After that, forked processes inherit the static variable which is already initialized with a value in the parent process.