This post summarizes Linux Kernel new features, bugfixes and changes in Linux 4.19.178 Release. Linux 4.19.178 Release contains 248 changes, patches or new features. In total, there are 239,909 lines of Linux source code changed/added in Linux 4.19.178 release compared to Linux 4.19 release. To view the source code of Linux 4.19.178 kernel release online,
Read more
Tag: gcc
Linux Kernel 5.4.102 Release
Posted onThis post summarizes Linux Kernel new features, bugfixes and changes in Linux 5.4.102 Release. Linux 5.4.102 Release contains 338 changes, patches or new features. In total, there are 160,715 lines of Linux source code changed/added in Linux 5.4.102 release compared to Linux 5.4 release. To view the source code of Linux 5.4.102 kernel release online,
Read more
Release Notes For Linux v2.0
Posted onThis is the release notes for linux release v2.0 (source code: linux-2.0.tar.gz) with format adjusted by removing/replacing tabs/spaces/new lines/formatting marks. This notes document can give us an understanding of the early development of the Linux kernel. The original ASCII formatted version is at the end of this post. Intro This document contains a list of
Read more
Release Notes For Linux v0.12
Posted onThis is the release notes for linux release v0.12 (source code: linux-0.12.tar.gz) with format adjusted by removing/replacing tabs/spaces/new lines. This notes document can give us an understanding of the very initial development of the Linux kernel. Also check Notes for linux release 0.01. The original ASCII formatted version is at the end of this post.
Read more
Release Notes For Linux v0.01
Posted onThis is the notes for linux kernel release 0.01 (source code: linux-0.01.tar.gz) with format adjusted by removing/replacing tabs/spaces/new lines. This notes document can give us an understanding of whether the Linux kernel started with its very first release. The original ASCII formatted version is at the end of this post. Notes for linux release 0.01
Read more
Converting Int to String in C++
Posted onIt 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
Read more
Change Another Process’ Environment Variables in Linux
Posted onEach 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
Read more
How to Install Hyperledger Fabric 2.0 in Ubuntu 18.04
Posted onHyperledger Fabric is a consortium blockchain system. It’s performance is relatively good and its modular architecture enables it to be usable in many scenarios. Hyperledger Fabric itself has rich documents and samples of test networks. For beginners, deploying a new network for trying and testing still consumes quite some time. In this post, we will
Read more
GCC May “Save” You Some Recursive Functions Calls: an Analysis of a Function Call Stack Length Example
Posted onWe know compilers like gcc can do lots smart optimization to make the program run faster. Regarding functions call optimization, gcc can do tail-call elimination to save the cost of allocating a new stack frame, and tail recursion elimination to turn a recursive function to non-recursive iterative one. gcc can even transform some recursive functions
Read more
How to Convert Integers to Strings and Strings to Integers in PHP
Posted onConversion from integer to string and from string to integer are common operations in most applications such as C++. PHP has its uniqueness in language and standard library design. In this post, we will check methods to convert integers to strings and vice versa. Convert string to int in PHP You can cast a string
Read more
A StoneWall Solution in C++
Posted onStoneWall is an interesting problem that requires some brain cycles yet not too complex. It is good software engineer interview question. Here is a C++ solution whose complexity is O(N). #include <stack> int solution(std::vector<int> &H) { int stones = 0; std::stack<int> heights; for (auto h: H) { while (!heights.empty() && h < heights.top()) { heights.pop();
Read more
How to Statically Link OCaml Programs
Posted onStatic linking is preferred for some cases although it has its own various problems. Static building/linking is not always possible for some languages on some platform. For OCaml, the answer to this question is yes. In this post, we will introduce 2 methods to statically linking OCaml: static linking with runtime glibc required and static
Read more
Installing Zlib Library in Ubuntu Linux
Posted onOn Ubuntu (18.04 and 20.04), installing zlib reported unable to locate package zlib: $ sudo apt install zlib Reading package lists… Done Building dependency tree Reading state information… Done E: Unable to locate package zlib How to install zlib in Ubuntu? Install zlib in Ubuntu from Ubuntu package repo In Ubuntu, the zlib package is
Read more
How to convert a string to lower case in Python?
Posted onHow to convert a string to lower case in Python? For example: “Abc” -> “abc” “BBB” -> “bbb” “abc” -> “abc” You can use the string.lower() method of Python: string.lower(s) Return a copy of s, but with upper case letters converted to lower case. Example: $ python Python 2.7.5 (default, Apr 11 2018, 07:36:10) [GCC
Read more
How to check whether a file of a given path is a block device in Python?
Posted onHow to check and test whether a file of a given path is a block device in Python? This can be Linux specific. You can use the os.stat() function to get the stat of the path. Then use the stat.S_ISBLK() function against the stat’s .st_mode to test whether it is a block device. An example:
Read more
How to test a file or directory exists in C++?
Posted onHow to test a path (a file or directory exists) in C++? In Bash, the [ -f ] and [ -d ] tests can test whether a file or a directory exist. What are the corresponding C++ ways for these tests? To test whether a file or dir (a path) exists, you may call stat()
Read more
How to decode a quoted URL in Python?
Posted onHow to decode a quoted URL in Python? For example, an quoted URL as follows https://www.example.com/tag/%E9%93%B6%E8%A1%8C/ should be decoded to https://www.example.com/tag/银行/ In Python 3, we can use `urllib.parse_plus()` (for URL only). One example is as follows. $ python3 Python 3.6.8 (default, Oct 7 2019, 12:59:55) [GCC 8.3.0] on linux Type “help”, “copyright”, “credits” or “license”
Read more
How to create a file if not exist and open it in read and write modes in C++?
Posted onHow to create a file if not exist and open it in read and write modes in C++? For example, I would like open a fstream on /tmp/cache to be able to read it and append to it. If the file does not exist yet, create one. A simple code like std::fstream fs(“/tmp/cache”, std::ios::in |
Read more
How to check whether a string starts with another string in C++?
Posted onHow to check whether a string starts with another string in C++? For example, startwith(“big string here…”, “big”) –> True and startwith(“big string here…”, “small”) –> False and startwith(“big”, “big string here”) –> False The std::string::compare() standard library function of C++ can be used. int compare( size_type pos1, size_type count1, const basic_string& str ) const;
Read more
How to split and iterate a string separated by a specific character in C++?
Posted onHow to split and iterate a string separated by a specific character in C++? For example, “a string separated by space” by ‘ ‘=> [“a”, “string”, “separated”, “by”, “space”] and “a,string,separated,by,comma” by ‘,’ => [“a”, “string”, “separated”, “by”, “comma”] C++ standard library’s getline() function can be used to build a function. getline() can accept a
Read more