Hello World of concurrency (using std::thread)

Now, let's get started with our first program using the std::thread library. You are expected to have C++ 11 or later to compile the programs we are going to discuss in this chapter. Let's take a simple, classic Hello World example as a reference before going into a multi-threaded Hello World:

//---- Thanks to Dennis Ritchie and Brian Kernighan, this is a norm for all languages
#include <iostream> 
int main() 
{ 
   std::cout << "Hello World\n"; 
} 

This program simply writes Hello World into the standard output stream (mainly the console). Now, let's see another example that does the same stuff, but using a background thread (often called a worker thread instead):

#include <iostream> 
#include <thread> 
#include <string> 
//---- The following function will be invoked by the thread library 
void thread_proc(std::string msg) 
{ 
   std::cout << "ThreadProc msg:" << msg; 
}  
int main() 
{ 
   // creates...