Book Image

Hands-On High Performance Programming with Qt 5

By : Marek Krajewski
5 (1)
Book Image

Hands-On High Performance Programming with Qt 5

5 (1)
By: Marek Krajewski

Overview of this book

Achieving efficient code through performance tuning is one of the key challenges faced by many programmers. This book looks at Qt programming from a performance perspective. You'll explore the performance problems encountered when using the Qt framework and means and ways to resolve them and optimize performance. The book highlights performance improvements and new features released in Qt 5.9, Qt 5.11, and 5.12 (LTE). You'll master general computer performance best practices and tools, which can help you identify the reasons behind low performance, and the most common performance pitfalls experienced when using the Qt framework. In the following chapters, you’ll explore multithreading and asynchronous programming with C++ and Qt and learn the importance and efficient use of data structures. You'll also get the opportunity to work through techniques such as memory management and design guidelines, which are essential to improve application performance. Comprehensive sections that cover all these concepts will prepare you for gaining hands-on experience of some of Qt's most exciting application fields - the mobile and embedded development domains. By the end of this book, you'll be ready to build Qt applications that are more efficient, concurrent, and performance-oriented in nature
Table of Contents (14 chapters)

Chapter 7

  1. Why will reading from std::cin first flush std::cout?
    Because they are tied by default—std::cin.tie(&std::cout);
  2. What is the difference between a unit-buffered, a line-buffered, a fully-buffered, and an unbuffered stream?
    A unit-buffered stream will flush after each >>, a line-buffered stream after each \n, a fully-buffered stream when the internal buffers are full, and unbuffered ones after each write.
  3. Why is std::iostream slower than std::filebuf and fprintf() slower that puts()?
    Because iostream will perform newline translation and locale-based conversions that filebuf doesn't have to. fprintf() must scan the format string in runtime; puts() doesn't have a format string.
    By the way, it is possible to scan a format string in compile time in C++ using template metaprogramming tricks!
  4. Why does Linux kill processes simply if it feels like it...