C++ :: Encapsulate Two Threads In A Class?
Apr 29, 2014how to encapsulate two threads in a class?
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Visual C++ :: How To Encapsulate WinAPI Dialog In A Class
Feb 28, 2013I have made a simple Pane class so that I can encapsulate a winapi Dialog.
I call it as:
Here the code I have, but it displays no dialog.
Here is what I do in main:
Code:
Pane(&hDlg, hInstance, nCmdShow);
while((ret = GetMessage(&msg, 0, 0, 0)) != 0)
{
if(ret == -1)
return -1;
if(!IsDialogMessage(hDlg, &msg))
{
[Code]...
C++ :: Threads Giving Error - Call Of Object Of A Class Type Without Appropriate Operator Or Conversion
Jan 27, 2015I made a simple binary tree then decide to try out threads too. I got the following error:
call of an object of a class type without appropriate operator or conversion
Code:
#include "Tree.h"
#include <iostream>
#include <thread>
void main(void){
[Code] ....
I am having a hard time figuring out why the error exists. I tried adding the new operator but that did not work.
C :: Use SIGNALS To Control Threads
Nov 11, 2013I've to use SIGNALS to control threads. Here's my code without the use of signals as I'm no good at that
Code:
#include <pthread.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
}
[code]....
C++ :: threads To Take Sequential Turns
Jun 30, 2014#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
int turn = 1;
int counter = 0;
int t, n;
[Code] ....
I found this program in a forum and it creates 1 to t threads with each thread pointing to the next and the last thread pointing to the first thread and it allows each thread to sequentially take a turn until all threads have taken n turns. That is when the program ends.
My doubt is if we see in void *tFunc(void *arg) function, first thread locks the mutex and then wait there forever till it's turn comes.Lets say if I spwan 1000 threads and they have take 10 turns each sequentially and what if a 550th thread locks the mutex as soon as the program starts and waiting for its turn which will never happen because still (turn=1) which means it's first thread's turn and first 549 threads have to complete their 1st turn before this 550 threda's turn comes.Doesnt this result in deadlock?
C++ :: Stopping Threads Without Using Local Var?
Aug 31, 2014Here's my code,
#include <iostream>
#include <unistd.h>
#include <thread>
using namespace std;
void Blink();
[Code] .....
The problem is i don't want to use local vars , is ther anyway do end the loop safely(removing all the vars used in function and etc) without using a local var ?
C/C++ :: Suspending And Resuming Threads
Apr 18, 2014#include <stdio.h>
#include <pthread.h>
int i; // loop control variable
int *id; // array used to pass parameter of id
int nThreads; // #threads
[Code]....
I want to know where I am going wrong. I am strong in java but not in c so that may be my problem.
C++ :: Creating And Terminating Threads?
Aug 31, 2014I had a requirement where i needed to create a thread and if the execution of thread is not completed in 5 minutes i needed to terminate its execution and continue with other part of the code.
I used the below code to create the thread
_beginthread(FuncnCall,0,NULL);
HANDLE hThread = GetCurrentThread();
Then after this code, I used the below code to check for 5 minutes
for (int i=1;i<=0;i++) {
printf("Value of i=%d
",i);
if(threadFinished) {
break;
} else {
Sleep(1000);
}
}
After this if the value of "threadFinished" is false then i am terminating the thread like below
if(threadFinished == false) {
TerminateThread(hThread,0);
CloseHandle(hThread);
}
The Problem here is, after terminating the thread, the program abruptly closes by giving fatal error. Looks like memory leakage is happening after terminating the thread. Is it not the right way to safely exit the thread?
C++ :: OpenMP - Intervals Assigned To Threads?
Feb 6, 2014Is there a way of knowing which indices a thread is assigned in a parallel openMP scope?
View 6 Replies View RelatedC :: Double Linked Structure Between 2 Threads
Jun 2, 2014I am on a little project involving TCP socket-programming and multiple threads but need passing structures between two threads.
The first thread receives data with respective ID, temp, etc,.. Each ID is a list-item of a linked list and every ID has again a linked list of all the received data.
The second thread just have to access the list and perform some manipulations on it.
My solution: pass the head pointer of the linked list. Easy enough, right? Somehow, I am stuck receiving error message:" dereferencing pointer to incomplete type."
For the sake of ease and simplicity I just added a stripped down version of the project.
The magic (or not) happens in MainProcess.c: The Data thread should receive the pointer (a think) from the Connection thread.
C++ :: Profiling Code - 4 Threads Slower Than 1
May 9, 2013I am doing something wrong since for me 4 threads perform 2 times slower then 1.I have 2 vectors with bunch of data to process, there is no concurrency (not moving elements and are independent of each other) so i just need to calculate some data from one and copy result in another.
LARGE_INTEGER getFrequency()
{
LARGE_INTEGER frequency;
QueryPerformanceFrequency(&frequency);
return frequency;
[code].....
C++ :: Create Two Threads Calling Even And Odd Functions
Mar 1, 2013I want to create two threads which will be calling even and odd functions where even function should print even number and odd function should print odd number.Can it be possible with condition variable? What is the code in both the cases i.e. two separate function and with condition variable.
View 6 Replies View RelatedC Sharp :: Stopping And Resuming Threads?
Jul 9, 2012how do I stop and restart a Thread in C# once it reaches a certain location on a form then restart the thread once it goes outside of the location boundries?
I am trying to stop an animation thread (a bullet) once it reaches a block on a panel.
C++ :: Threads Never Execute In Arbitrary Order?
Jul 25, 2014Code:
void Arrival_MainThread::Body () {
t1 = new boost::thread((Arrive_Fctor()), 2);
t2 = new boost::thread((Arrive_Fctor()), 10000);
t3 = new boost::thread((Arrive_Fctor()), 3000);
Code:
class Arrive_Fctor {
public:
void operator()(int mean) {
m_Arrivals = new Arrivals(mean);
m_Arrivals->Activate();
#ifndef NO_RESOURCE
[code].....
The order of arrivals always appear as 3,2,1 it can't be 1,2,3 or 3,1,2 or something like that?
The body method is called when m_Arrival->Activate() is executed, and it is running as an independent thread.
Visual C++ :: Can Two Functions In Same DLL Be Called By Two Threads?
Aug 27, 2014I write a DLL MyDLL.dll with Visual C++ 2008, as follows:
(1)MFC static linked
(2)Using multi-thread runtime library.
In the DLL, this is a global data m_Data shared by two export functions, as follows:
ULONGLONG WINAPI MyFun1(LPVOID *lpCallbackFun1) {
...
Write m_Data(using Critical section to protect)
[Code]....
Although MyThread1 and MyThread2 using critical section to protect the shared data m_Data, I will still suspend MyThread1 before accessing the shared data, to prevent any possible conflicts.
The problem is:
(1)When the first invoke of MyFun2, everything is OK, and the return value of MyFun2(that is nResult2) is 1 , which is expected.
(2)When the second, third and fourth invoke of MyFun2, the operations in MyFun2 are executed successfully, but the return value of MyFun2(that is nResult2) is a random value instead of the expected value 1. I try to using Debug to trace into MyFun2, and confirm that the last return statement is just return a value of 1, but the invoker will receive a random value instead of 1 when inspecting nResult2.
(3)After the fourth invoke of MyFun2 and return back to the next statement follow MyFun2, I will always get a "buffer overrun detected" error, whatever the next statement is.
I think this looks like a stack corruption, so try to make some tests:
1.I confirm the /GS (Stack security check) feature in the compiler is ON.
2.If MyFun2 is invoked after MyFun1 in MyThread1 is completed, then everything will be OK.
3.In debug mode, the codeline in MyFun2 that reads the shared data m_Data will not cause any errors or exceptions. Neither will the codeline in MyFun1 that writes the shared Data.
C++ :: Accessing And Working With Vector From Multiple Threads
Oct 20, 2014I have a vector that I would like to access and work with from multiple threads. I have created an example below to illustrate the functionality that I would like to accomplish.
The goals are to be (1) high speed, (2) thread safe, and (3) *if possible* continue to use vectors as my larger project uses vectors all over the place and as such I would like to maintain that.
However, if I need to switch from vectors to something else then I am open to that as well.
The following example below compiles but crashes rather quickly because it is not thread safe.
How I can fix the example below which I can then apply to my larger project?
#include <string>
#include <vector>
#include <ctime>
#include <thread>
#include <iostream>
#include <random>
#include <atomic>
#include <algorithm>
enum EmployeeType {
[Code] ....
C++ :: Solving Linear System Of Equations Using Threads
Dec 14, 2014I am trying to write a code that solves a system of linear equations such as A*B=C. My system has a dimension equal to 1600. The matrix A cab be separated into 4 sub matrices and each can be handled by a different thread. I tried to solve this using the following code:
int main() {
int count = 0;
//Inputing matrix A
ifstream matrix;
matrix.open("example.txt");
[Code] ....
Although the above code gives the correct answer, the time needs to find the solution is bigger than that needed without using threads.
C++ :: Reading / Writing File On Multiple Threads?
Aug 7, 2013I'm currently working on a server for handling clients in a 2d online game and I wrote some regular fstream file code for handling the file that stores their information and I was about to implement it into the server, then I realized there might be a problem having it open multiple times concurrently, so I googled it and came up with
posts like
[URL]
I'm wondering if I can just treat it like everything else or will I have to do something specific for opening on multiple threads?
p.s. I did read those posts but I'm very new to multithreading
C++ :: Passing Data Between Threads Without Using Global Variables
Nov 6, 2013I have a main thread and a worker thread. How do i pass data between them when both are already running without using global variables?
View 1 Replies View RelatedC :: Consumer And Producer Threads Aren't Synchronizing Correctly?
Dec 3, 2013I have a school assignment to create a program that uses a producer thread to create a series of random numbers, and a consumer thread to read those numbers (via a shared bounded buffer), and record the min, max, average, and number of items. Now, the threads aren't synching well. Here's my code:
Code:
#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
pthread_cond_t empty;
pthread_cond_t full;
int done = 0;
pthread_mutex_t lock;
[code] ....
And output:
Code:
Producer in for
Consumer Entering While
Consumer reading item 0
Producer making item 0
Consumer reading item 1
Consumer reading item 2
Consumer reading item 3
Producer making item 1
Producer making item 2
Producer making item 3
Producer making item 4
Producer making item 5
Producer making item 6
Consumer reading item 4
Minimum: 0
Maximum: 4978
Average: 995
Items Produced: 5
C++ :: Chat Messenger - Running Multiple Threads At Same Time
Sep 18, 2013I'm doing work on chat messenger and facing difficulty to run multiple threads at the same time. Here is the sample code.
void menu();
void groupChat();
void personalChat();
int main() {
sf::Thread thread(&menu());
thread.launch();
[Code] ....
In my program, after menu when he selects a choice, next display of menu wait the termination of the selected thread.
while i want to show menu right after when a menu is selected.
C++ :: Instance Of Class A Vs Class B Derived From Class A
Jul 3, 2014There are two ways to access the members of class A inside class B:
1) Making an instance of class A in class B
2) Deriving class B from class A
So what is the basic difference in both ways as we can do same kind of work with both ways?
C++ :: How To Get Object Of Original Class From Function Of Other Class Where Other Class Object Is Member Of Original Class
Jan 21, 2013The case is like
class B{
public:
somedata;
somefunction();
}
class A{
public:
data;
function();
}
in somefunction i want a pointer to current object of class A m new to c++
C++ :: Calling Derived Class Functions In A Function With Parameter Of Base Class
Mar 30, 2013Say I have 3 classes:
class Player {
public:
virtual func1();
[code]....
Say in my main class, I have a function fight(Player p1, Player p2) and I would like to do something like this in the fight function, given that p1 is the human and p2 is the computer:
//function fight()
fight(Player p1, Player p2) {
p1.func2();
}
//using function fight()
fight(human, computer);
When I compile the program, I got this: error: ‘class Player’ has no member named 'func2()' What can I do to allow p1 to call func2 inside fight()? I'm not allowed to use pointers as the parameter for fight() and have to use the signature fight(Player p1, Player p2).
C++ :: Size Of Derived Class With Overriding Virtual Functions From Base Class?
Jan 21, 2014The compiler creates virtual table for the base class and also for the derived class whether we override it or not.
That means each class has separate virtual table. when we get the size of the each class with out any data members... the size of base is -- 4 bytes(64 bit) and the size of derived is -- 1
The size of base class 4 is correct since it creates the virtual pointer internally and its size is member data + virtual pointer, but it in this case I have included any data members so it has given 4 byts.
But why in case of derived is 1 byte, since it the derived class has overridden the virtual function from base, this will also contains the virtual pointer which will be pointing to derived class Vtable, it the size of the class suppose to be 4 instead of 1 byte.
#include<iostream>
class A{
public:
[Code].....
C++ :: Transfer Values Set In Privates Of Base Class By Object Of One Derived Class To Another
Apr 26, 2014I have my main.cpp like this:
#include <iostream>
#include "curve1.h"
#include "curve2.h"
using namespace std;
int main() {
Curve1 curve1Obj;
Curve2 curve2Obj;
[Code]...
Base class Score has two derived classes Curve1 and Curve2. There are two curve() functions, one is in Curve1 and other in Curve2 classes. getSize() returns the value of iSize.
My base class header score.h looks like this:
#ifndef SCORE_H
#define SCORE_H
class Score {
private:
int *ipScore;
float fAverage;
int iSize;
[Code]...
You can see that I have used curve1Obj to enter scores, calculate average and output. So if I call getSize() function with cuve1Obj, it gives the right size that I took from user in enterScores() function. Also the result is same if I call getSize() in score.cpp definition file in any of the functions (obviously).
.....
The problem is when I call curve() function of Curve2 class in main (line 23) with the object curve2Obj, it creates a new set of ipScore, fAverage and iSize (i think?) with garbage values. So when I call getSize() in curve() definition in curve2.cpp, it outputs the garbage. .....
How can I cause it to return the old values that are set in curve1.cpp?
Here is my curve2.cpp
#include <iostream>
#include "curve2.h"
using namespace std;
void Curve2::curve() {
cout << "getSize() returns: " << getSize() << endl; // out comes the garbage
}
Can I use a function to simply put values from old to new variables? If yes then how?