C / C++ / MFC

• Standard C (no assembler).
• Can run on "any" microcontroller (of course, it needs to have a certain amount of RAM and flash).
• No use of malloc.
• If running on ARM and there's nothing to do and all timers are turned off, then it should enter stop mode (=system clock is turned off).
• If running on ARM and there's nothing to do but at least one timer is running, then it should enter sleep mode (=some peripherals are turned off, but the system clock and timers are still working).
• Needs to have some sort of prioritization, for example, low-level driver tasks needs to be handled before higher level tasks (such as tasks that arisen due to, for example, a push button pressed event) may be handled.
• It needs to, in some way, support calling of asynchronous functions, such as starting a DMA-transfer and then you get an interrupt when it's finished and in between it should execute other tasks.  

void (*taskFunctionPtr_t)(uint32_t arg1, uint32_t arg2)
enum queueSelector_e {LOW_LEVEL_DRIVERS, USER_EVENTS}; 
addTaskToQueue(taskFunctionPtr_t, queueSelector_e);

while (TRUE) {
    if (0 < numQueuedTasks(LOW_LEVEL_DRIVERS)) {
        handleTask(LOW_LEVEL_DRIVERS);
        continue;
    }
    if (0 < numQueuedTasks(USER_EVENTS)) {
        handleTask(USER_EVENTS);
        continue;
    }
    if (anyTimerRunning()) {
        enterIdleMode();  // System clock is still running, but some peripherals (not the timers!) are turned off
    } else {
        enterStopMode();  // System clock is turned off and can only be woken up user event (external int)
    }
}

void (*asynchronousTaskFinishedFunctionPtr)(asynchronousTaskResult_e);
void someAsynchronousFunction(asynchronousTaskFinishedFunctionPtr); 
enum asyncTaskStatus_e {TASK_NOT_STARTED, TASK_IN_WAIT_PHASE, TASK_FINISHED_NEEDS_REPEAT_DUE_TO_ERROR, TASK_SUCCESSFULLY_FINISHED}; 
asyncTaskStatus_e (*getAsyncTaskStatusPtr)();
addSynchronousTaskToQueue(taskFunctionPtr_t, queueSelector_e);
addAsynchronousTaskToQueue(taskFunctionPtr_t, queueSelector_e, getAsyncTaskStatusPtr);

while (TRUE) {
    Bool_t taskIsInWaitPhase;
    if (0 < numQueuedTasks(LOW_LEVEL_DRIVERS)) {
        taskIsInWaitPhase = handleTask(LOW_LEVEL_DRIVERS);
        if (!taskIsInWaitPhase) {
            continue;
        }
    }
    if (0 < numQueuedTasks(USER_EVENTS)) {
        taskIsInWaitPhase = handleTask(USER_EVENTS);
        if (!taskIsInWaitPhase) {
            continue;
        }
    }
    if (anyTimerRunning() || atLeastOneTaskInWaitPhase()) {
        enterIdleMode();  // System clock is still running, but some peripherals (not the timers!) are turned off
    } else {
        enterStopMode();  // System clock is turned off and can only be woken up user event (external int)
    }
}

// Returns whether the current task is in wait phase or not
Bool_t handleTask(queueSelector_e) {
    if (taskIsAsynchronous()) {
        if (asynchronousTaskStatus == TASK_SUCCESSFULLY_FINISHED) {
            incrementTaskQueueReadPointer();
        } else if ((asynchronousTaskStatus == TASK_NOT_STARTED) || 
                   (asynchronousTaskStatus == TASK_FINISHED_NEEDS_REPEAT_DUE_TO_ERROR)) {
            callTaskFunction();
        } else if (asynchronousTaskStatus == TASK_IN_WAIT_PHASE) {
            // Do nothing
            return TRUE; 
        }
    } else {
        callTaskFunction();
        incrementTaskQueueReadPointer();
    }
    return FALSE;
}

void longTask(uint32_t arg1, uint32_t arg2) {
    enum partSelector_e {
       PART1,
       PART2,
       PART3,
       PART4,
       PART5
    };
    static partSelector_e partSelector = PART1;
    switch (partSelector) {
        case PART1: 
            do1stPartOfLongTask();
            partSelector++;
            repeatThisTask();  // Tell scheduler to repeat this task (scheduler will not increment task queue read ptr)
            return;
        case PART1: 
            do2ndPartOfLongTask();
            partSelector++;
            repeatThisTask();  // Tell scheduler to repeat this task (scheduler will not increment task queue read ptr)
            return;
        case PART3: 
            do3rdPartOfLongTask();
            partSelector++;
            repeatThisTask();  // Tell scheduler to repeat this task (scheduler will not increment task queue read ptr)
            return;
        case PART4: 
            do4thPartOfLongTask();
            partSelector++;
            repeatThisTask();  // Tell scheduler to repeat this task (scheduler will not increment task queue read ptr)
            return;
        case PART5: 
            do5thPartOfLongTask();
            partSelector = PART1;
            return;
    }
}

// This is a task, not an interrupt handler (in the interrupt handler, the following function was added to the USER_EVENTS queue)
void button1pressedTask(uint32_t arg1, uint32_t arg2) {
    readADC();         // Synchronous call, no problem
    setPinHigh();      // Synchronous call, no problem
    startDMAtransfer   // Asynchronous call, MAJOR PROBLEMS!!!! Scheduler needs to able to handle higher priority tasks here!
    writeI2Cdata();    // Synchronous call, no problem
    writeUARTdata();   // Synchronous call, no problem
}

String Area = AreaCBox.Text;
          DAL.CaseBarCode csbrt = new DAL.CaseBarCode();
          System.Data.DataSet csbrs = csbrt.GetPO(Area);
          foreach (DataRow dr in csbrs.Tables[0].Rows)
          {

              POCBox.Items.Add(dr["ProductionOrder"]);

          }

//  Demonstrate dynamic_cast on template classes.
#include <iostream>
using namespace std;

template <class T>
class Num {
protected:
    T val;
public:
    Num(T x) { val = x;}
    virtual T getval() {    return val;    }
};

template <class T>
class SqrNum : public Num<T> {
public:
    SqrNum(T x) : Num<T>(x) {}
    T getval()  {   return (val * val);   }
};

int main(){
    Num<int> *bp, numInt_ob(2);
    SqrNum<int> *dp, sqrInt_ob(3);
    Num<double> numDouble_ob(3.3);

    bp = dynamic_cast<Num<int>*> (&sqrInt_ob);          //sqrInt_ob is from a derived class of Num<int>.
    if(bp) {
        cout << "Cast from sqrNum<int>* to Num<int>* OK.\n"
             << "Value is " << bp->getval() << endl;
    }
    else
        cout << "Error !\n\n";

    dp = dynamic_cast<SqrNum<int>> (&numInt_ob);        //numInt_ob is base class object and SqrNum is a derived class.
    if(dp)
        cout << "Error !\n";
    else {
        cout << "Cast from Num<int>* to SqrNum<int>* not OK.\n"
             << "Can't cast a pointer to a base object into\n"
             << "a pointer to a derived object\n\n";
    }

    bp = dynamic_cast<Num<int>*> (&numDouble_ob);        //Num<int> of type int & numDouble_ob is of type Num<double>
    if(bp)
        cout << "Error" << endl;
    else {
        cout << "Can't cast from Num<double>* to Num<int>*.\n"
             << "These are 2 different types.\n\n";
    }

    return 0;
}

Quote:

error: 'val' was not declared in this scope
T getval() { return (val val); }
^~~

Quote:

class SqrNum : public Num<t>

//  Demonstrate dynamic_cast on template classes.
#include <iostream>
using namespace std;

template <class T>
class Num {
protected:
    T val;
public:
    Num(T x) { val = x;}
    virtual T getval() {    return val;    }
};

template <class T>
class SqrNum : public Num<T> {
public:
    SqrNum(T x) : Num<T>(x) {}
    T getval()  {   return (Num<T>::val * Num<T>::val);   }
};

int main(){
    Num<int> *bp, numInt_ob(2);
    SqrNum<int> *dp, sqrInt_ob(3);
    Num<double> numDouble_ob(3.3);

    bp = dynamic_cast<Num<int>*> (&sqrInt_ob);          //sqrInt_ob is from a derived class of Num<int>.
    if(bp) {
        cout << "Cast from sqrNum<int>* to Num<int>* OK.\n"
             << "Value is " << bp->getval() << endl;
    }
    else
        cout << "Error !\n\n";

    dp = dynamic_cast<SqrNum<int>*> (&numInt_ob);        //numInt_ob is base class object and SqrNum is a derived class.
    if(dp)
        cout << "Error !\n";
    else {
        cout << "Cast from Num<int>* to SqrNum<int>* not OK.\n"
             << "Can't cast a pointer to a base object into\n"
             << "a pointer to a derived object\n\n";
    }

    bp = dynamic_cast<Num<int>*> (&numDouble_ob);        //Num<int> of type int & numDouble_ob is of type Num<double>
    if(bp)
        cout << "Error" << endl;
    else {
        cout << "Can't cast from Num<double>* to Num<int>*.\n"
             << "These are 2 different types.\n\n";
    }

    return 0;
}