Tutorials and tips on C++ language, libraries and techniques.
Resource Acquisition Is Initialization (RAII) is a fundamental programming idiom in C++ that ties the lifecycle of a resource—memory, file handles, network sockets, database connections, locks—to the lifecycle of an object. When the object is created, the resource is acquired. When the object is destroyed and goes out of scope, the resource is automatically released….
RTTI is a C++ mechanism that allows you to determine an object’s type at runtime. It’s essential when working with polymorphism and inheritance hierarchies, but it comes with trade-offs you need to understand. Key RTTI Operators typeid() — Returns a std::type_info object representing the type. You can compare type information or get a human-readable name…
Unlike Python or JavaScript, C++ doesn’t provide a built-in split() method for strings. You’ll need to use library functions or write your own utility. The best approach depends on your compiler version, performance requirements, and whether you’re handling edge cases. The Classic Approach: find() and substr() The most straightforward method uses std::string::find() to locate delimiters…
std::vector is the right default choice for almost every container need in C++. It’s the foundation of high-performance applications—game engines, financial systems, data processing pipelines—because it aligns with how modern CPUs actually work. Cache Locality Drives Performance std::vector stores elements in contiguous memory. When you iterate, the CPU prefetches the next elements into L1/L2 cache,…
The Linux kernel includes a USB host controller driver for the Maxim MAX3421E chip, which implements a USB 2.0 full-speed and low-speed host controller over SPI. This was introduced in commit 2d53139 by David Mosberger-Tang and is maintained in the kernel’s USB subsystem. Overview The MAX3421E is a specialized chip that allows SPI-connected systems to…
Converting integers to strings is a frequent operation in C++ programs. Modern C++ provides several approaches, each with different trade-offs in simplicity, performance, and flexibility. Using std::to_string() (Recommended) The standard library function std::to_string() (C++11 and later) is the most straightforward approach for most use cases: #include <iostream> #include <string> int main() { int n =…
Each process on Linux has its own environment variable namespace. While normally isolated, there are scenarios where you might need to modify a running process’s environment—usually for debugging, testing, or dynamic configuration changes. The standard approach uses GDB’s ability to call functions within a running process. This works by attaching GDB to the target process…
Hyperledger Fabric is a modular, enterprise-grade consortium blockchain platform. While its official documentation is comprehensive, deploying a test network from scratch requires configuring multiple dependencies and tools—a process that’s time-consuming for new users. This guide covers both automated and manual setup approaches to get a working Fabric network running quickly. Prerequisites You’ll need: Ubuntu 24.04…
The StoneWall problem is a classic algorithmic challenge that tests your ability to recognize when a stack data structure enables a greedy O(N) solution. The Problem Given an array of wall heights, determine the minimum number of distinct stone blocks needed to construct that height profile. Each stone block can be placed multiple times at…
C++20 introduced std::string::starts_with(), which is the most straightforward way to check if a string begins with a specific substring: #include <iostream> #include <string> int main() { std::string text = “big string here…”; std::cout << std::boolalpha; std::cout << text.starts_with(“big”) << std::endl; // true std::cout << text.starts_with(“small”) << std::endl; // false std::cout << text.starts_with(“big string”) << std::endl;…
Splitting strings by a delimiter is a common task in systems programming. C++ doesn’t provide a built-in split function like Python, but you can implement one efficiently using the standard library. Using std::istringstream and getline() The standard approach uses std::istringstream with std::getline(). The getline() function accepts a delimiter parameter, allowing you to extract tokens until…
For iterating through directories and files in C++, you have several options depending on your needs and C++ standard version. Using <filesystem> (C++17 and Later — Recommended) The modern approach uses std::filesystem, which is cleaner, safer, and handles cross-platform differences for you: #include <filesystem> #include <iostream> #include <string> namespace fs = std::filesystem; int ListDir(const std::string&…
Stripping newlines from strings is common when processing text input, especially from files or network streams. Here are the practical approaches. Using erase() with std::remove() The most efficient method combines std::remove() and erase() — this is the erase-remove idiom: #include <iostream> #include <algorithm> #include <string> int main() { std::string input{“line 1\n\n\nline 3\nline 4”}; std::cout <<…
The stat() system call is the standard way to retrieve file metadata on Linux, including modification time (mtime). It’s fast, portable, and gives you access to nanosecond-precision timestamps. Basic Approach with stat() #include <sys/stat.h> #include <stdio.h> struct stat st; if (stat(“path/to/file”, &st) == -1) { perror(“stat failed”); return 1; } printf(“Mtime (seconds): %ld\n”, st.st_mtime); printf(“Mtime…
Determining whether a path points to a directory or regular file is a common task in system programming. You need to stat the path and inspect the file mode. Using lstat() and stat macros The lstat() system call retrieves file metadata into a struct stat. For a given path, you can use the standard macros…
In C++, you have several ways to output to standard output and standard error streams. The choice depends on your project’s requirements and whether you’re working with older codebases or modern C++. Using std::cout and std::cerr The standard approach uses the C++ iostream library: #include <iostream> int main() { std::cout << “This goes to standard…
To retrieve the parent process ID (PPID) of the current running process, use the getppid() system call. This is the standard and portable approach on Unix-like systems including Linux. #include <stdio.h> #include <unistd.h> int main() { pid_t ppid = getppid(); printf(“Parent process ID: %d\n”, ppid); return 0; } Compile and run: gcc -o get_ppid get_ppid.c…
Retrieving the hostname of the current system is a common task in systems programming, network applications, and monitoring tools. C++ provides several approaches depending on your platform and requirements. Using gethostname() The most portable approach uses the gethostname() function from <unistd.h>: #include <unistd.h> #include <iostream> #include <cstring> int main() { char hostname[256]; if (gethostname(hostname, sizeof(hostname))…
YouCompleteMe’s installation script fails on Fedora with a CMake error about missing PYTHON_LIBRARIES and PYTHON_INCLUDE_DIRS, even when Python is already installed. The error looks like this: CMake Error at /usr/share/cmake/Modules/FindPythonLibs.cmake:201 Could NOT find PythonLibs (missing: PYTHON_LIBRARIES PYTHON_INCLUDE_DIRS) The issue is that you have the Python runtime libraries installed but not the development headers needed for…
Designated initializers for aggregate types with non-trivial members (like std::vector) have inconsistent support across GCC versions. This error typically appears when you try to initialize a struct containing standard library containers using designated initializer syntax in the wrong order. The Problem When you compile this code with older GCC versions: struct Stat { vector<int> vec;…