Beginning threading

Sorry for the uninformative title, but here's my problem I want to do (the example I'm providing is very similar to John the Ripper cracking utility, where you press the spacebar and it prints some data). I made a little picture of what I think my program should look like (graphic representation) here: http://img.photobucket.com/albums/v2...o1/threads.jpg

So, the problem is that I need this data generator thread to be spinning away somewhere, while another (thread? just the parent?) is waiting for an event like keyboard input to do something else. So, I don't even know where to start on this one. Critical sections sound interesting, mutexes also, but all in all I don't know where to look for a solution to my problem. MSDN is an infinite library of information but I don't know how I would go about applying the things given. With my limited knowledge, I was able to create this very simple simple thread:

Code:

---

#include <iostream>
#include <string>
#include <windows.h>
using namespace std;


string s = "aaaa";
DWORD WINAPI Generator(void *Params) {
    // This is just an example section
    // to spit out some data to query
    // or something
    int i = 0;               
    int length = s.length();
   

    while(s[i]++)
    {         
          while(s[i] == 'z' + 1) {
                s[i] = 'a';
                s[++i]++;
          }
          if(i == length) { break; }
          i = 0;
    }
    return 0;
}
int main(int argc, char* argv[]) {
    HANDLE hThread;
    DWORD dwThread;

    hThread = CreateThread(NULL, NULL,
            Generator,  // Function pointer
            (void*) 0,  // Arguments
            NULL, &dwThread);
     

    if (hThread) { return WaitForSingleObject(hThread,INFINITE); }
    else { return 1; }
}

---

This just runs the function in a thread and then let's the WaitForSingleObject run infinitely until it returns. Naturally instead of this WaitForSingleObject, I want to be able to interact with this thread or something, or set up another thread which does stuff while this other thread is spinning about, and I have really, no direction for doing something like that. Any tips? It's all greatly appreciated.

Multithreading for Rookies

gg

Thank you for the link! However, I think that I have fallen onto a Windows thread hook instead. This seems to me, the best way to simulate event driven programming for win32 C. But, unfortunently, I really am not very good with Windows hooks! Here is the code that I currently have, problems I encountered below:

Code:

---

#define _WIN32_WINNT 0x0400

#include <windows.h>
#include <iostream>
#include <string>
using namespace std;


HHOOK    hKeywait; // The keyboard hook var
string s = "aaa";  // "Bruteforce" string


LRESULT CALLBACK FilterFunction(int nCode, WORD wParam, DWORD lParam) {
        cout << s << endl;
        // This is a test and it appears
        // this proc is never actually being
        // called. Shouldn't the hook be
        // doing something to get us here??

        if  (wParam == WM_KEYDOWN)     
        {
               
        }
        return CallNextHookEx(hKeywait, nCode, wParam, lParam);
}



DWORD WINAPI Generator(void *Params) {
        // Function runs in a thread, creating
        // all combo's of a string a-z for length
        // of the global "bruteforce" variable
       
        int i = 0;               
        int length = s.length();
 

        while(s[i]++)
        {         
                while(s[i] == 'z' + 1) {
                        s[i] = 'a';
                        s[++i]++;
                }
                if(i == length) { break; }
                i = 0;
        }
        return 0;
}


void MsgLoop()
{
        // This code spins about spitting messages
        // everywhere. Will the WM_KEYDOWN message
        // ever get to the FilterProc? I dunno
        MSG message;
        while (GetMessage(&message,NULL,0,0)) {
                TranslateMessage( &message );
                DispatchMessage( &message );
        }
}



int main(int argc, char* argv[]) {
        DWORD    dwThread;
        HANDLE    hThread;
       

        hThread = CreateThread
                (NULL, NULL, Generator,
                (void*) 0, NULL, &dwThread);




        hKeywait = SetWindowsHookEx (
                WH_KEYBOARD,                // Local process keyboard thread hook
                (HOOKPROC) FilterFunction,  // "Hook proc", which confuses me
                (HINSTANCE) NULL,          // Null, hook proc isn't in DLL mod
                (DWORD) hThread );          // Thee local thread to hook from


        MsgLoop();
        UnhookWindowsHookEx(hKeywait);
        return 0;
}

---

Well, this code might look familiar to what is described in a NewOrder article about a keylogger here: http://neworder.box.sk/newsread.php?newsid=10952 because a lot of the topics seem fairly relevent (even though my goal is hardly a keylogger here). So, my problem here, is that it does not seem we ever actually get to my filter procedure, however from what I was lead to believe (I probably read the diagram wrong) from this image: http://msdn.microsoft.com/library/en.../hooks32_1.gif is that the hook add's the FilterProc to the chain, and starts being executed and such.

I'm probably wrong in my interpretation here, and I don't really know what I'm doing. Any help is much appreciated.

I would forget about threads and hooks - you don't need either for "even driven programming".

gg

I don't know, sorry, I've fallen back to the WaitForStuff series. I think that for this, I am going to have to have a (worker thread?) generating data in one place, while something else is checking the console for keypresses or "events". I think I want to use a WaitForMultipleObjects, the two objects being a handle to STDIN and another to the thread, but I do not know how to implement this. In fact, I do not even know how to do a WaitForSingleObject(hStdin, INFINITE). Like:

Code:

---

int main() {
    CreateAllTheThreadsEtc();
    HANDLE hStdin = GetStdHandle(STD_INPUT_HANDLE);


    while(WaitForSingleObject(hStdin, INFINITE) == WAIT_OBJECT_0) {
        cout << somedata << endl;
    }
    return 0;
}

---

Just continuously cout's stuff, without waiting. Maybe I do not understand the concept of something being signaled? If I banged my head on the keyboard would it be signaled? While I was looking around, I found this (win32 getch() thing) http://faq.cprogramming.com/cgi-bin/...&id=1043284392 but I think I kind of failed at adopting the techniques to here.

At this point what I need to try to do, is

1) Do "stuff" when the program finds that the console has recieved input
2) (Less important) find a way to stop doing step 1 when hThread finishes

Thanks again

>> but I think I kind of failed at adopting the techniques to here.

Code:

---

#include <iostream>
using namespace std;

#include <conio.h> // for getch(), kbhit()
#include <windows.h> // for Sleep()

void key_pressed()
{
    int c = getch();
    cout << "Key pressed: " << char(c) << endl;
}//key_pressed

void do_other_stuff()
{
    Sleep(0);
}//do_other_stuff

int main()
{
    while (1)
    {
        if (kbhit())
            key_pressed();
        else
            do_other_stuff();
    }//while

    return 0;
}//main

---

For learning windows programming (including coverage of multi-threading): http://www.microsoft.com/mspress/books/toc/2344.asp

gg