[[File:1stblock1stblock2.png|1000px|center|serial]]

On the Threads window, you can see "main thread" and other new three thread which same as default usable thread number 4 (The number is maximum usable thread of the cpu the program is running. And it is printed in the serial region as "omp_get_max_threads()"). after hitting 4 times (you can see the count on the breakpoint Window), the step goes to the next region.[[File:2ndtblockticon.png|50px|center|open]]A thread icon appear the side of the parallel line[[File:2ndblock2.png|1000px|center|open]]

[[File:3rdblock3rdblock2.png|1000px|center|open+]]

We Each of these programs will use be a separate project.   <source lang="c">//Source1.cpp#include <iostream>#include <iomanip>#include <cstdlib>#include <chrono>#include <omp.h>#define NUM_THREADS 8using namespace std::chrono; // report system time//void reportTime(const char* msg, steady_clock::duration span) { auto ms = duration_cast<milliseconds>(span); std::cout << msg << " - took - " << ms.count() << " milliseconds" << std::endl;} int main(int argc, char** argv) { if (argc != 2) { std::cerr << argv[0] << ": invalid number of arguments\n"; std::cerr << "Usage: " << argv[0] << " no_of_slices\n"; return 1; } int n = std::atoi(argv[1]); steady_clock::time_point ts, te;  // calculate pi by integrating the following area under 1/(1 + x^2 programs ) in n steps ts = steady_clock::now(); int numThreads, f; double x, pi; double stepSize = 1.0 / (double)n; double sum[NUM_THREADS]; omp_set_num_threads(NUM_THREADS);#pragma omp parallel { int tid = omp_get_thread_num(); int nt = omp_get_num_threads(); if (tid == 0) numThreads = nt; sum[tid] = 0.0; for (int i = tid; i < n; i = i + nt) {  x = ((double)i + 0.5) * stepSize; sum[tid] += 4.0 / (1.0 + x * x); //std::cout << "THREAD" << tid << std::endl; } } int nt = omp_get_num_threads(); for (f = 0, pi = 0.0; f < numThreads; f++) { pi += sum[f] * stepSize; }  //pi = 4.0 * sum * stepSize; te = steady_clock::now();  std::cout << "n = " << n << std::fixed << std::setprecision(15) << "\n pi(exact) = " << 3.141592653589793 << "\n pi(calcd) = " << pi << std::endl; reportTime("Integration", te - ts);  // terminate char c; std::cout << "Press Enter key to debugg exit ... "; std::cin.get(c);} </source><source lang="c"> //Source2.cpp#include <iostream>#include <iomanip>#include <cstdlib>#include <chrono>#include <omp.h>#define PAD 8#define NUM_THREADS 1using namespace std::chrono; // report system time//void reportTime(const char* msg, steady_clock::duration span) { auto ms = duration_cast<milliseconds>(span); std::cout << msg << " - took - " << ms.count() << " milliseconds" << std::endl;} int main(int argc, char** argv) { if (argc != 2) { std::cerr << argv[0] << ": invalid number of arguments\n"; std::cerr << "Usage: " << argv[0] << " no_of_slices\n"; return 1; } int n = std::atoi(argv[1]); steady_clock::time_point ts, te;  // calculate pi by integrating the area under 1/(1 + x^2 processes) in n steps ts = steady_clock::now(); double x, pi = 0.0; double sum[NUM_THREADS][PAD]; double stepSize = 1.0 / (double)n; //double sumArr[8];  omp_set_num_threads(NUM_THREADS);#pragma omp parallel { int tid = omp_get_thread_num(); int nt = omp_get_num_threads();  for (int i = tid; i < n; i = i + nt) { x = ((double)i + 0.5) * stepSize; sum[tid][0] += 1.0 / (1.0 + x * x); //std::cout << "THREAD" << tid << std::endl; } }  for (int i = 0, pi = 0.0; i++;)pi += sum[i][0] * stepSize; //pi = 4.0 * sum * stepSize; te = steady_clock::now();  std::cout << "n = " << n << std::fixed << std::setprecision(15) << "\n pi(exact) = " << 3.141592653589793 << "\n pi(calcd) = " << pi << std::endl; reportTime("Integration", te - ts);

Each of these programs will be a separate project // terminate char c; std::cout << "Press Enter key to exit ... "; std::cin.get(c);}

'''Start Multiple Projects'''

PIC[[File:Pr1.png|1000px|center|Process window]]  3.Navigate to the Source2 project's project file and open it  [[File:Pr2.png|600px|center|Process window]] 

Next we will have to set the 2nd Source2 project to start up with the 1st Source1 project

4.Select Start as the action for the 2nd Source2 Project

[[File:Pr4.png|600px|center|Process window]]  Now when we run the debugger, it will run both projects as a seperate processand will show up on the Processes window.  [[File:Pr5.png|1000px|center|Process window]]  The Processes Window will show: *Name: Name of the process*ID: Process ID*Path to the executable*Title: Menu Bar Title*State: Break or Running*Debugging:Debugging (Native, Managed, and so on.)*Connection Type: Transport type (default, native with no authentication)*Connection Target: Transport Qualifier (remote computer)   

'''Attach debugger to background process'''

First we must run the 2nd Source2 project without the debugger (VS 2017 will not allow you to attach as a running background process that is using the debugger).

[[File:Pr6.png|300px|center|Process window]]  4.Apply the changes and then under tools, select your command line tool 5.In the commandline, navigate to the 2nd Source2 project's debug folder*The executable should be located in the projects Debug folder*If there is no debug folder, you must run the Source2 project at least once 6.In the commandline, type the name of the Source2 project with the .exe extension and the appropriate agruements and the press enter to execute*IMPORTANT: Do not press enter to continue, Visual Studios only allow the debugger to attach to a running process  [[File:Pr7.png|600px|center|Process window]]

1.Start Debugging 2.Select Debug and pick Attach to Process  [[File:Pr8.png|1000px|center|Process window]]  3.In the Attach to Process window, select Source2 project's process and click attach  [[File:Pr9.png|600px|center|Process window]]

Now your debugger will run the 1st Source1 project with 2nd Source2 project as a seperate process