Access a class instance based on its ID

[meerokh]

I have two queues in my program,queue and waitingQueue. queue contains the workpackage instances that are created by user . After creating a workpackge by a user, if he decides to yield it, i want to change the status of created workpackage to waiting and add it to the waitingQueue. Creation of workpackage returns a unique id of the package that is added to the queue. This is what i want to acheive:

//Done in user application
int packageId = creatpackage(Function, arguments); // this create a package and adds it to a normal queue
wait(packageId); //wait call yeild function that is part of my library

//Inside library
void classname::yeild(int packageId){
set the state of workpackage to Waiting
add the package to WaitingQueue
if(there is another package in WaitingQueue)
Make a switch context to it
else
Go to normal queue and execute the package
}

My question is how can i access the workpackage state after which yeild function was called. I thought of accessing it based on id somehow(is it even possible??) Based on my full scenario, is there any better approach then what i am doing??

[Lost User]

In theory yes, you can do it that way. But you need some mechanism to find the actual object from the id. When you call the creatpackage function, where does it keep all the data related to that package?

[meerokh]

It got stored in an instance of class WorkPackage which in turn is added to packagequeue WorkPackage.h

class WorkPackage {
private:
WorkPackageState wp_state;
void (*m_action)(void*);
void* m_arguments = nullptr;
protected:
static int id;

public:
WorkPackage(){};
WorkPackage(void (*action)(void*), void* arguments);
void destroystack();
void execute();
static void setState(WorkPackageState wp_state);
WorkPackageState getState();
Stack Wp_localstack;
fcontext_t m_context;
int packageId;
};

Workpackage.cpp

WorkPackage::WorkPackage(void (*action)(void*), void* arguments) {
Wp_localstack.local_stack= Stack::make_stack();
m_action = action;
m_arguments = arguments;
Wp_localstack.local_stack = static_cast (Wp_localstack.local_stack) + 1000;
m_context = make_fcontext(Wp_localstack.local_stack, 1000, m_action);
wp_state = running;
packageId=++id;
}

WorkPackageState WorkPackage::getState() {
return state;
}

void WorkPackage::execute(int thread_id) {
m_action(m_arguments);
destroystack();
}

void WorkPackage::setState(WorkPackageState state) {
WorkPackageState new_state = state;
}

[Lost User]

So, I guess, packagequeue is the place to find it.