Hi, I'm Tomasz

I'm a professional C++ software engineer with over a decade of hands on development experience with variety of technologies (mostly Linux & embedded systems). This is my blog.

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Interview question that became a meme

How to reverse a linked list? Yep! This headline says it all. For some reason, for quite a while, this was (hopefully it’s no longer) a very popular problem given during technical interviews. Why that might be? Probably because it’s a simple problem to solve, interviewers don’t have to prepare themselves to use it and it has a couple of solutions so, it’s a good conversation starter about algorithms and performance in regards to time & space complexity.

My favourite design pattern: The Observer

Why Observer is so cool? Managing complexity in large code base is all about decoupling. Observer is a perfect tool to do that. The Observed object has no idea about its observers, no dependency injection is required at all, as a result a loose coupling is achieved between two classes of objects where the only common part is the interface they agree upon. First iteration It’s a classic design pattern and I’m sure majority (if not all) of engineers know the details behind it, most of us implement it in a slightly different way, depending on the requirements and the code base we are working with though.

Handling signals in Linux with C++

Why signals are important Signals are the simplest form of IPC in Unix-like systems. They are notifiers to the process that an external event has happened. As this is a system specific mechanism, there’s no portable C++ STL library providing support for signal handling. But it’s fairly easy to write one. First though a short introduction is required. Signal disposition Each thread in a process has a signal mask which can be modified either via setprocmask (for single threaded processes) or pthread_sigmask (for multithreaded processes).

Callbacks in C++ API design

Callbacks are a perfect way for clients to interface with an API abstracting an events source. How to design an API for such abstraction to make it unambiguous and easy to use? The simplest choice is functor injection, similarly as it is done in many places in STL (or even C stdlib by means of function pointers). Can we do better though? What are the alternatives available? In this post, I’ll try to provide a step by step overview of a design process for an imaginary HttpServer class.