Send a variable on the heap to another thread
- by user1201889
I have a strange problem in C++. An address of a Boolean gets "destroyed" but it doesn't get touched. I know that there are beater way's to accomplish what I try to do, but I want to know what I do wrong.
I have a main class; this main class contains a vector of another class. There is a strange problem when a new instance gets created of this object.
This is how my code works:
There will start a thread when the constructor gets called of the “2nd”object. This thread gets as Parameter a struct. This is the struct:
struct KeyPressData
{
vector<bool> *AutoPressStatus;
vector<int> *AutoPressTime;
bool * Destroy;
bool * Ready;
};
The struct gets filled in the constructor:
MultiBoxClient::MultiBoxClient()
{
//init data
DestroyThread = new bool;
ReadyThread = new bool;
AutoThreadData = new KeyPressData;
//Reseting data
*DestroyThread = false;
*ReadyThread = false;
//KeyPressData configurating
AutoThreadData->AutoPressStatus = &AutoPressStatus;
AutoThreadData->AutoPressTime = &AutoPressTime;
AutoThreadData->Destroy = DestroyThread;
AutoThreadData->Ready = ReadyThread;
//Start the keypress thread
CreateThread(NULL,NULL,(LPTHREAD_START_ROUTINE)AutoKeyThread,AutoThreadData,NULL,NULL);
}
As long as the constructor is running will the program run fine. But when the constructor closes the address of the “AutoThreadData-Destroy” will get corrupted. The program will crash when I call the value of the pointer.
void WINAPI AutoKeyThread(void * ThreadData)
{
KeyPressData * AutoThreadData = (KeyPressData*)ThreadData;
while(true)
{
if(*AutoThreadData->Destroy == true) //CRASH
{
*AutoThreadData->Ready = true;
return;
}
Sleep(100);
}
}
What did I test:
I logged the address of the AutoThreadData and the AutoThreadData-Destroy when the constrcutor is running and clossed; the AutoThreadData address is equal to AutoThreadData when the constructor is closed. So there is no problem here.
The address of AutoThreadData-Destroy gets destroyed when the constructor is closed. But how can this happen? The Boolean is on the heap and the KeyPressData struct (AutoThreadData) is on the heap.
Destroy before: 00A85328
Destroy after: FEEEFEEE
Can someone maby explain why this crash?
I know that I can send a pointer to my class to the thread. But I want to know what goes wrong here. That way I can learn from my mistakes.
Could someone help me with this problem?
Thanks!
