How to create a Singleton in C?

Question

What\'s the best way to create a singleton in C? A concurrent solution would be nice.

I am aware that C isn\'t the first language you would use for a singleton.

Answer 1

Here's another perspective: every file in a C program is effectively a singleton class that is auto instantiated at runtime and cannot be subclassed.

• Global static variables are your private class members.
• Global non static are public (just declare them using extern in some header file).
• Static functions are private methods
• Non-static functions are the public ones.

Give everything a proper prefix and now you can use my_singleton_method() in lieu of my_singleton.method().

If your singleton is complex you can write a generate_singleton() method to initialize it before use, but then you need to make sure all the other public methods check if it was called and error out if not.