Initial example and concepts

Author: mpavezb

.gitignore

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+.clangd/
+build/
+bin/
+*.html
+
+# Created by https://www.gitignore.io/api/c++,cmake,emacs
+# Edit at https://www.gitignore.io/?templates=c++,cmake,emacs
+
+### C++ ###
 # Prerequisites
 *.d
 
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 *.exe
 *.out
 *.app
+
+### CMake ###
+CMakeLists.txt.user
+CMakeCache.txt
+CMakeFiles
+CMakeScripts
+Testing
+Makefile
+cmake_install.cmake
+install_manifest.txt
+compile_commands.json
+CTestTestfile.cmake
+_deps
+
+### CMake Patch ###
+# External projects
+*-prefix/
+
+### Emacs ###
+# -*- mode: gitignore; -*-
+*~
+\#*\#
+/.emacs.desktop
+/.emacs.desktop.lock
+*.elc
+auto-save-list
+tramp
+.\#*
+
+# Org-mode
+.org-id-locations
+*_archive
+
+# flymake-mode
+*_flymake.*
+
+# eshell files
+/eshell/history
+/eshell/lastdir
+
+# elpa packages
+/elpa/
+
+# reftex files
+*.rel
+
+# AUCTeX auto folder
+/auto/
+
+# cask packages
+.cask/
+dist/
+
+# Flycheck
+flycheck_*.el
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+# server auth directory
+/server/
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+# projectiles files
+.projectile
+
+# directory configuration
+.dir-locals.el
+
+# network security
+/network-security.data
+
+
+# End of https://www.gitignore.io/api/c++,cmake,emacs

CMakeLists.txt

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+cmake_minimum_required(VERSION 3.16)
+project(cpp_concurrency)
+
+if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX)
+ set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror -Wall -Wno-long-long -pedantic")
+endif()
+
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+enable_testing()
+add_subdirectory(src)

README.md

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 # cpp_concurrency
  Code for the Modern C++ Concurrency in Depth course from Udemy. 
+
+## Concepts
+
+Process: Is defined by its instructions and current state.
+
+Context Switching:
+- The OS can store the state of a process or thread, so that it can be restored and resume execution at a later point. 
+- This allows multiple processes to share a single central processing unit (CPU), and is an essential feature of a multitasking operating system.
+
+Round-Robin Scheduling:
+- Assigns time-slots to each process in equal portions and circular order, having no priorities.
+- Context switching is performed when a time slot is completed.
+- Simple and starvation-free.
+- See: https://en.wikipedia.org/wiki/Round-robin_scheduling
+
+Task- and Data- Level Parallelism:
+- Task-Level: Threads perform different tasks (using the same or different data).
+- Data-Level: Threads perform the same task on different data.
+
+Parallelism vs Concurrency:
+- Parallelism: When each process/thread runs on a dedicated processor at the same time.
+- Concurrency: Emulated parallelism based on context-switching (sequencial execution!).
+- True parallelism is difficult to achieve, due to the low number of cores usually available.
+
+Heterogeneous Computing:
+- Refers to systems that use more than one kind of processor or cores. 
+- These systems gain performance or energy efficiency by using specialized hardware.
+- https://en.wikipedia.org/wiki/Heterogeneous_computing
+
+GPGPU (General Purpose GPU):
+- Is the use of a GPU to handle tasks a CPU would do.
+- The idea is to handle matrix-like data using the GPU.
+- See: https://en.wikipedia.org/wiki/General-purpose_computing_on_graphics_processing_units
+
+## Building the code
+
+```bash
+sudo apt install gcc-10 g++-10 # C++20
+
+mkdir -p build && cd build
+cmake -D CMAKE_C_COMPILER=gcc-10 -D CMAKE_CXX_COMPILER=g++-10 .. && make
+
+-std=c++20 -fcoroutines -pthread
+```

src/0_thread.cpp

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+#include <cstdio>
+#include <iostream>
+#include <ostream>
+#include <thread>
+
+void foo() {
+ auto id = std::this_thread::get_id();
+ std::cout << "Hello from funciton foo. Thread ID:" << id << std::endl;
+}
+
+class Bar {
+public:
+ void operator()() {
+ auto id = std::this_thread::get_id();
+ std::cout << "Hello from functor Bar.Thread ID:" << id << std::endl;
+ }
+};
+
+int main() {
+ std::thread thread1(foo);
+
+ Bar bar;
+ std::thread thread2(bar);
+
+ std::thread thread3([] {
+ auto id = std::this_thread::get_id();
+ std::cout << "Hello from lambda.Thread ID:" << id << std::endl;
+ });
+
+ thread1.join();
+ thread2.join();
+ thread3.join();
+ std::cout << "Hello from main." << std::endl;
+ return 0;
+}

src/CMakeLists.txt

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+project(src) # can this be deleted?
+
+#find_package(Boost REQUIRED)
+#include_directories(${Boost_INCLUDE_DIRS})
+
+add_executable(0_thread 0_thread.cpp)
+target_link_libraries(0_thread pthread)