What is Ethereum? Ethereum is a decentralized, open-source blockchain platform that enables developers to build and deploy smart contracts and decentralized applications (dApps). Launched in 2015 by Vitalik Buterin, it is often described as the “world computer” because it allows code to run exactly as programmed without downtime, censorship, or third-party interference. A Brief History…
Resource Acquisition Is Initialization (RAII) in C++ RAII is a fundamental programming idiom in C++ that ties the lifecycle of a resource (like memory, file handles, or network sockets) to the lifecycle of an object. When the object is created, the resource is acquired; when the object is destroyed (goes out of scope), the resource…
Splitting a String by Another String in C++: A Flexible Utility Unlike Python or JavaScript, C++ doesn’t have a built-in split() method for strings. However, there are several ways to achieve this, from manual loops to modern C++20/23 ranges. The Classic Approach: std::string::find The most common way to split a string is by using find…
Why std::vector is the Optimal Choice for Data Structures for Performance in C++ In almost every case, std::vector should be your default choice for a container in C++. It is the backbone of high-performance C++ applications, from game engines to financial modeling. The Secret: Cache Locality std::vector stores its elements in contiguous memory. This means…
We may use two lists to store the values of two properties of a list of elements in Python. Under such data structure arrangement, when we need to sort the properties from one list, we may want to also make sure the other list will be also re-ordered following the same order as the first…
This post summarizes Linux Kernel new features, bugfixes and changes in Linux 5.4.72 Release. Linux 5.4.72 Release contains 23 changes, patches or new features. In total, there are 126,508 lines of Linux source code changed/added in Linux 5.4.72 release compared to Linux 5.4 release. To view the source code of Linux 5.4.72 kernel release online,…
This change “Add support for using a MAX3421E chip as a host driver.” (commit 2d53139) in Linux kernel is authored by David Mosberger <davidm [at] egauge.net> on Mon Apr 28 22:14:07 2014 -0600. Description of “Add support for using a MAX3421E chip as a host driver.” The change “Add support for using a MAX3421E chip…
It is common to convert an integer (int) to a string (std::string) in C++ programs. Because of the long history of C++ which has several versions with extended libraries and supports almost all C standard library functions, there are many ways to convert an int to string in C++. This post introduces how to convert…
R is a language and environment for statistical computing and graphics, providing a wide variety of statistical and graphical techniques. The R environment is open source software under GPL. R has rich software packages and is widely used for statistical analysis. RStudio Server is an R integrated development environment (IDE) that provides many useful features…
This change “drm/i915/guc: Don’t enable GuC/HuC in auto mode on pre-Gen11” (commit 87d855e) in Linux kernel is authored by Michal Wajdeczko <michal.wajdeczko [at] intel.com> on Fri Jul 12 11:14:44 2019 +0000. Description of “drm/i915/guc: Don’t enable GuC/HuC in auto mode on pre-Gen11” The change “drm/i915/guc: Don’t enable GuC/HuC in auto mode on pre-Gen11” introduces changes…
This change “PM / clk: Fix clock error check in __pm_clk_add()” (commit 3fc3a0b) in Linux kernel is authored by Geert Uytterhoeven <geert+renesas [at] glider.be> on Fri May 8 10:47:43 2015 +0200. Description of “PM / clk: Fix clock error check in __pm_clk_add()” The change “PM / clk: Fix clock error check in __pm_clk_add()” introduces changes…
This change “netpoll: fix netconsole IPv6 setup” (commit 00fe11b) in Linux kernel is authored by Sabrina Dubroca <sd [at] queasysnail.net> on Thu Feb 6 18:34:12 2014 +0100. Description of “netpoll: fix netconsole IPv6 setup” The change “netpoll: fix netconsole IPv6 setup” introduces changes as follows. netpoll: fix netconsole IPv6 setup Currently, to make netconsole start…
This change “cifs: release auth_key.response for reconnect.” (commit f5c4ba8) in Linux kernel is authored by Shu Wang <shuwang [at] redhat.com> on Fri Sep 8 18:48:33 2017 +0800. Description of “cifs: release auth_key.response for reconnect.” The change “cifs: release auth_key.response for reconnect.” introduces changes as follows. cifs: release auth_key.response for reconnect. There is a race that…
This post summarizes new features, bugfixes and changes in Linux kernel release 4.19.70. Linux 4.19.70 Release contains 95 changes, patches or new features. In total, there are 101,521 lines of Linux source code changed/added in Linux 4.19.70 release compared to Linux 4.19 release. To view the source code of Linux 4.19.70 kernel release online, please…
This change “ALSA: hda/realtek – Fix Headphone Mic doesn’t recording for ALC256” (commit d32b666) in Linux kernel is authored by Kailang Yang <kailang [at] realtek.com> on Thu Apr 23 15:10:53 2015 +0800. Description of “ALSA: hda/realtek – Fix Headphone Mic doesn’t recording for ALC256” The change “ALSA: hda/realtek – Fix Headphone Mic doesn’t recording for…
This change “fs: handle SEEK_HOLE/SEEK_DATA properly in all fs’s that define their own llseek” (commit 06222e4) in Linux kernel is authored by Josef Bacik <josef [at] redhat.com> on Mon Jul 18 13:21:38 2011 -0400. Description of “fs: handle SEEK_HOLE/SEEK_DATA properly in all fs’s that define their own llseek” The change “fs: handle SEEK_HOLE/SEEK_DATA properly in…
How to Count the Number of Words in a File in PHP Counting words in a file is a common task in text processing. In PHP, there are several efficient ways to do this, even for large files. Method 1: The Simple One-Liner For small to medium files, you can read the whole file into…
Linux allows more than one users to log into the system to run processes/programs at the same time. In order to make this multi-user system work properly, Linux provides ways to isolate and protect users from each other and manage the permissions efficiently. One of the mechanism is user groups. Linux users may be grouped…
Python is one of the most popular programming languages in the world. It is widely popular for a plethora of tasks due to its flexible nature and ease of use. Python has also managed to beat other programming languages such as Java, which were once upon a time, the world’s favorite. In fact, the extent…
Each process has its environment variables in Linux. But is it possible to change another process’ environment variable from another process in Linux? If it is possible to do so, how to do it? There is a trick which can work for some scenarios. First, find out the process ID, then start gdb and attach…