Quick Answer

Missing object instance for member function call

Understanding the Issue

Non-static member functions require an object instance to operate on. This error occurs when trying to call them like static functions.

The Problem

This code demonstrates the issue:

Cpp Error 
// Problem: Static call to instance method
class Logger {
public:
    void log(string msg) {}
};
Logger::log("error"); // Error

The Solution

Here's the corrected code:

Cpp Fixed 
// Solution 1: Create instance
Logger logger;
logger.log("error");

// Solution 2: Make static
static void log(string msg) {} // Then Logger::log() works

Key Takeaways

Non-static methods require an object instance.