Insufficient pointer usage

Modern C++ provides smart pointers such as std::unique_ptr and std::shared_ptr to manage dynamic memory more safely and efficiently. It’s generally better to use std::unique_ptr instead of raw pointers for exclusive ownership. When multiple actors need to share ownership of a resource, std::shared_ptr can be used. However, there are common issues related to the misuse of std::shared_ptr.

Building std::shared_ptr

Using the constructor of std::shared_ptr to create an object leads to separate allocations for the control block and the managed object:

std::shared_ptr<int> create() {
    std::shared_ptr<int> ptr(new int(42));
    return ptr;
}

A better approach is to use std::make_shared, which combines the allocations into a single memory block, improving performance and cache locality:

std::shared_ptr<int> create() {
    return std::make_shared<int>(42);...