New Posts  All Forums:Forum Nav:

[C++] Questions - Page 5

post #41 of 91
That's not going to work because generic pointers don't have members. As I said before, you need to cast it to a pointer to a ThreadData. Static binding is done based on datatype. If your variable does not have the correct type, the binding cannot be done.

Typing is VERY important in C/C++ 2cents.gif
Edited by jpz - 1/24/11 at 2:41pm
BlackBox
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 3.6ghz @ 1.35V Gigabyte X38-DS4 ATI 5870 4GB Corsair Dominator 1033Mhz 
Hard DriveOSMonitorKeyboard
Hitachi P7K500 320GB 64-bit Gentoo Linux / 64-bit Vista Ultimate Sceptre X24-WG 24" WUXGA Deck 82-key 
PowerCaseMouse
Corsair 750TX BlackBox (scratch built) Logitech G5 
  hide details  
Reply
BlackBox
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 3.6ghz @ 1.35V Gigabyte X38-DS4 ATI 5870 4GB Corsair Dominator 1033Mhz 
Hard DriveOSMonitorKeyboard
Hitachi P7K500 320GB 64-bit Gentoo Linux / 64-bit Vista Ultimate Sceptre X24-WG 24" WUXGA Deck 82-key 
PowerCaseMouse
Corsair 750TX BlackBox (scratch built) Logitech G5 
  hide details  
Reply
post #42 of 91
Thread Starter 
I'm afraid I don't understand what you're telling me to do.

Got a link to somewhere that explains it? I can take a look over it tomorrow and try again.
Megadoomer
(14 items)
 
Family Computer
(13 items)
 
 
CPUMotherboardGraphicsRAM
Phenom II X6 1090T @ 4.0Ghz ASUS M4A89GTD PRO Sparkle GTS 450 2x4GB G-Skill Sniper 
Hard DriveCoolingOSMonitor
Samsung F1 1TB CM Hyper 212+ Windows 7 Professional x64 Samsung T220 
KeyboardPowerCaseMouse
Logitech MX3000 Laser CM 1000M HAF 922 Logitech VX Revolution 
CPUMotherboardGraphicsRAM
Q6600 Asus PN5-D 750i Evga GTS 250 2x2GB Crucial Ballistix 
Hard DriveOptical DriveOSMonitor
750GB Hitachi Samsung Super Writemaster Windows 7 Professional x64 19" Dell 
PowerCase
Corsair 450VX Antec 900 
  hide details  
Reply
Megadoomer
(14 items)
 
Family Computer
(13 items)
 
 
CPUMotherboardGraphicsRAM
Phenom II X6 1090T @ 4.0Ghz ASUS M4A89GTD PRO Sparkle GTS 450 2x4GB G-Skill Sniper 
Hard DriveCoolingOSMonitor
Samsung F1 1TB CM Hyper 212+ Windows 7 Professional x64 Samsung T220 
KeyboardPowerCaseMouse
Logitech MX3000 Laser CM 1000M HAF 922 Logitech VX Revolution 
CPUMotherboardGraphicsRAM
Q6600 Asus PN5-D 750i Evga GTS 250 2x2GB Crucial Ballistix 
Hard DriveOptical DriveOSMonitor
750GB Hitachi Samsung Super Writemaster Windows 7 Professional x64 19" Dell 
PowerCase
Corsair 450VX Antec 900 
  hide details  
Reply
post #43 of 91
Ok. Input is a ThreadData object, correct? Only ThreadData objects have members called seconds, ThreadID, etc. Therefore you can only access those members if your object variable has the type ThreadData. If you are using pointers(which is the case in your worker function) your variable needs to be a pointer to a ThreadData object. Right now your variable is of type LPVOID which is probably just a fancy typedef for void*. Essentially the variable has no type, so when you try to access member functions and datamembers of the variable in your worker thread the compiler does not know where to find these datamembers or member functions. This is because the compiler uses the variable type to determine where those datamembers and memberfunctions are so it can bind the code together.

In your worker thread, cast Input back to a pointer to a ThreadData:
ThreadData* p_Input = (ThreadData*) Input;

Now you can access Input's members:

cout << "Running for seconds: " << p_Input->seconds << endl;

Seems to me like you could use a refresher on pointers.
BlackBox
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 3.6ghz @ 1.35V Gigabyte X38-DS4 ATI 5870 4GB Corsair Dominator 1033Mhz 
Hard DriveOSMonitorKeyboard
Hitachi P7K500 320GB 64-bit Gentoo Linux / 64-bit Vista Ultimate Sceptre X24-WG 24" WUXGA Deck 82-key 
PowerCaseMouse
Corsair 750TX BlackBox (scratch built) Logitech G5 
  hide details  
Reply
BlackBox
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 3.6ghz @ 1.35V Gigabyte X38-DS4 ATI 5870 4GB Corsair Dominator 1033Mhz 
Hard DriveOSMonitorKeyboard
Hitachi P7K500 320GB 64-bit Gentoo Linux / 64-bit Vista Ultimate Sceptre X24-WG 24" WUXGA Deck 82-key 
PowerCaseMouse
Corsair 750TX BlackBox (scratch built) Logitech G5 
  hide details  
Reply
post #44 of 91
Thread Starter 
Ok, so this is the code I've got now:

Code:

DWORD WINAPI worker(LPVOID Input)
{
  ThreadData* Data = (ThreadData*) Input;
  
  
  cout << "Running for seconds: " << Data->seconds << endl;  
  cout << "Closing thread..." << endl;

It compiles just fine, but while seconds should be 1, it's instead some random 10mil+ integer, as if the variable hasn't been initialised.

So I tried changing the function from:
DWORD WINAPI worker(LPVOID Input)
to
DWORD WINAPI worker(ThreadData* Input)

But then the CreateThread() function started giving errors.

Quote:
Originally Posted by jpz View Post
Seems to me like you could use a refresher on pointers.
I know... I intend to go over it properly before the exam.
Megadoomer
(14 items)
 
Family Computer
(13 items)
 
 
CPUMotherboardGraphicsRAM
Phenom II X6 1090T @ 4.0Ghz ASUS M4A89GTD PRO Sparkle GTS 450 2x4GB G-Skill Sniper 
Hard DriveCoolingOSMonitor
Samsung F1 1TB CM Hyper 212+ Windows 7 Professional x64 Samsung T220 
KeyboardPowerCaseMouse
Logitech MX3000 Laser CM 1000M HAF 922 Logitech VX Revolution 
CPUMotherboardGraphicsRAM
Q6600 Asus PN5-D 750i Evga GTS 250 2x2GB Crucial Ballistix 
Hard DriveOptical DriveOSMonitor
750GB Hitachi Samsung Super Writemaster Windows 7 Professional x64 19" Dell 
PowerCase
Corsair 450VX Antec 900 
  hide details  
Reply
Megadoomer
(14 items)
 
Family Computer
(13 items)
 
 
CPUMotherboardGraphicsRAM
Phenom II X6 1090T @ 4.0Ghz ASUS M4A89GTD PRO Sparkle GTS 450 2x4GB G-Skill Sniper 
Hard DriveCoolingOSMonitor
Samsung F1 1TB CM Hyper 212+ Windows 7 Professional x64 Samsung T220 
KeyboardPowerCaseMouse
Logitech MX3000 Laser CM 1000M HAF 922 Logitech VX Revolution 
CPUMotherboardGraphicsRAM
Q6600 Asus PN5-D 750i Evga GTS 250 2x2GB Crucial Ballistix 
Hard DriveOptical DriveOSMonitor
750GB Hitachi Samsung Super Writemaster Windows 7 Professional x64 19" Dell 
PowerCase
Corsair 450VX Antec 900 
  hide details  
Reply
post #45 of 91
I think we need the whole code to be able to tell what you're trying to do and what needs to be done for it to work.
post #46 of 91
Thread Starter 
I posted the majority of it a few posts above.
Megadoomer
(14 items)
 
Family Computer
(13 items)
 
 
CPUMotherboardGraphicsRAM
Phenom II X6 1090T @ 4.0Ghz ASUS M4A89GTD PRO Sparkle GTS 450 2x4GB G-Skill Sniper 
Hard DriveCoolingOSMonitor
Samsung F1 1TB CM Hyper 212+ Windows 7 Professional x64 Samsung T220 
KeyboardPowerCaseMouse
Logitech MX3000 Laser CM 1000M HAF 922 Logitech VX Revolution 
CPUMotherboardGraphicsRAM
Q6600 Asus PN5-D 750i Evga GTS 250 2x2GB Crucial Ballistix 
Hard DriveOptical DriveOSMonitor
750GB Hitachi Samsung Super Writemaster Windows 7 Professional x64 19" Dell 
PowerCase
Corsair 450VX Antec 900 
  hide details  
Reply
Megadoomer
(14 items)
 
Family Computer
(13 items)
 
 
CPUMotherboardGraphicsRAM
Phenom II X6 1090T @ 4.0Ghz ASUS M4A89GTD PRO Sparkle GTS 450 2x4GB G-Skill Sniper 
Hard DriveCoolingOSMonitor
Samsung F1 1TB CM Hyper 212+ Windows 7 Professional x64 Samsung T220 
KeyboardPowerCaseMouse
Logitech MX3000 Laser CM 1000M HAF 922 Logitech VX Revolution 
CPUMotherboardGraphicsRAM
Q6600 Asus PN5-D 750i Evga GTS 250 2x2GB Crucial Ballistix 
Hard DriveOptical DriveOSMonitor
750GB Hitachi Samsung Super Writemaster Windows 7 Professional x64 19" Dell 
PowerCase
Corsair 450VX Antec 900 
  hide details  
Reply
post #47 of 91
Take a look at this example of CreateThread() and see if you can figure it out: http://msdn.microsoft.com/en-us/libr...=vs.85%29.aspx

int Data = 0;
...
Data = *((int*)lpParam);
...

This is in the DisplayMessage() function from the code you've provided. Data is an integer type but the data passed to the DisplayMessage() function is a pointer, so you need to type cast this pointer to integer in order to get it's value.

So (int*)lpParam casts the pointer to an integer type pointer. Then * (<integer pointer>) gets the value of the integer pointed to by <integer pointer>. You'll have to look at more examples of pointers, how to access the data pointed at by a pointer, and type casting pointers.
Edited by mrwalker - 1/24/11 at 3:30pm
post #48 of 91
It very well may not be getting initialized. Check your code in main().

The compiler should be giving you a warning if it is possible that a variable is not initialized. I find it quite helpful to turn on all compiler warnings if you have not done so already. Some people hate warnings and prefer to hide them, but experience tells me that good compilers will find many of the problems you miss long before you encounter them and try to warn you about them. Then again I work primarily with gcc and g++ which I doubt you're using because you're working with the Windows API, and the Windows API itself might generate tons of warnings so it may be less useful in your case to enable all the warnings.

Another piece of advice- it's better to review pointers sooner rather than later. The time spent reviewing will quickly pay for itself because you will spend much less time struggling with pointers on your assignments and you'll avoid the frustration of debugging programs that contain code with improper pointer use.
BlackBox
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 3.6ghz @ 1.35V Gigabyte X38-DS4 ATI 5870 4GB Corsair Dominator 1033Mhz 
Hard DriveOSMonitorKeyboard
Hitachi P7K500 320GB 64-bit Gentoo Linux / 64-bit Vista Ultimate Sceptre X24-WG 24" WUXGA Deck 82-key 
PowerCaseMouse
Corsair 750TX BlackBox (scratch built) Logitech G5 
  hide details  
Reply
BlackBox
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 3.6ghz @ 1.35V Gigabyte X38-DS4 ATI 5870 4GB Corsair Dominator 1033Mhz 
Hard DriveOSMonitorKeyboard
Hitachi P7K500 320GB 64-bit Gentoo Linux / 64-bit Vista Ultimate Sceptre X24-WG 24" WUXGA Deck 82-key 
PowerCaseMouse
Corsair 750TX BlackBox (scratch built) Logitech G5 
  hide details  
Reply
post #49 of 91
Thread Starter 
Well, I'm only using the Windows API for this function;t the rest fo the code is all pretty standard C++... nothing too complicated there. Also, this is the last assignment I'll have before the exam. Just need to get this threading out of the way.

Anyway, thanks for the help everyone. I'm going to sleep now, and will tackle it again tomorrow.
Megadoomer
(14 items)
 
Family Computer
(13 items)
 
 
CPUMotherboardGraphicsRAM
Phenom II X6 1090T @ 4.0Ghz ASUS M4A89GTD PRO Sparkle GTS 450 2x4GB G-Skill Sniper 
Hard DriveCoolingOSMonitor
Samsung F1 1TB CM Hyper 212+ Windows 7 Professional x64 Samsung T220 
KeyboardPowerCaseMouse
Logitech MX3000 Laser CM 1000M HAF 922 Logitech VX Revolution 
CPUMotherboardGraphicsRAM
Q6600 Asus PN5-D 750i Evga GTS 250 2x2GB Crucial Ballistix 
Hard DriveOptical DriveOSMonitor
750GB Hitachi Samsung Super Writemaster Windows 7 Professional x64 19" Dell 
PowerCase
Corsair 450VX Antec 900 
  hide details  
Reply
Megadoomer
(14 items)
 
Family Computer
(13 items)
 
 
CPUMotherboardGraphicsRAM
Phenom II X6 1090T @ 4.0Ghz ASUS M4A89GTD PRO Sparkle GTS 450 2x4GB G-Skill Sniper 
Hard DriveCoolingOSMonitor
Samsung F1 1TB CM Hyper 212+ Windows 7 Professional x64 Samsung T220 
KeyboardPowerCaseMouse
Logitech MX3000 Laser CM 1000M HAF 922 Logitech VX Revolution 
CPUMotherboardGraphicsRAM
Q6600 Asus PN5-D 750i Evga GTS 250 2x2GB Crucial Ballistix 
Hard DriveOptical DriveOSMonitor
750GB Hitachi Samsung Super Writemaster Windows 7 Professional x64 19" Dell 
PowerCase
Corsair 450VX Antec 900 
  hide details  
Reply
post #50 of 91
Ah, I thought this was one of your first assignments and your exam would be in the spring. In that case good luck on your exam!
BlackBox
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 3.6ghz @ 1.35V Gigabyte X38-DS4 ATI 5870 4GB Corsair Dominator 1033Mhz 
Hard DriveOSMonitorKeyboard
Hitachi P7K500 320GB 64-bit Gentoo Linux / 64-bit Vista Ultimate Sceptre X24-WG 24" WUXGA Deck 82-key 
PowerCaseMouse
Corsair 750TX BlackBox (scratch built) Logitech G5 
  hide details  
Reply
BlackBox
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 3.6ghz @ 1.35V Gigabyte X38-DS4 ATI 5870 4GB Corsair Dominator 1033Mhz 
Hard DriveOSMonitorKeyboard
Hitachi P7K500 320GB 64-bit Gentoo Linux / 64-bit Vista Ultimate Sceptre X24-WG 24" WUXGA Deck 82-key 
PowerCaseMouse
Corsair 750TX BlackBox (scratch built) Logitech G5 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Coding and Programming