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- volatile in c
- structure padding in c
Volatile in multi-threaded applications
Despite the presence of queues, pipes, and other scheduler-aware communications mechanisms in real-time operating systems, it is still fairly common for two tasks to exchange information via a shared memory location (that is, a global). When you add a pre-emptive scheduler to your code, your compiler still has no idea what a context switch is or when one might occur. Thus, another task modifying a shared global is conceptually identical to the problem of interrupt service routines discussed previously. So all shared global variables should be declared volatile. For example:
int cntr;
void task1(void)
{
cntr = 0;
while (cntr == 0)
{
sleep(1);
}
...
}
void task2(void)
{
...
cntr++;
sleep(10);
...
}
This code will likely fail once the compiler's optimizer is enabled. Declaring cntr to be volatile is the proper way to solve the problem.
We provide Volatile in multi-threaded applications for the educational purposes only. We do not responsiable for the correctness of its contents. the risk of using it lies entirelywith the user.
int cntr;
void task1(void)
{
cntr = 0;
while (cntr == 0)
{
sleep(1);
}
...
}
void task2(void)
{
...
cntr++;
sleep(10);
...
}
This code will likely fail once the compiler's optimizer is enabled. Declaring cntr to be volatile is the proper way to solve the problem.
We provide Volatile in multi-threaded applications for the educational purposes only. We do not responsiable for the correctness of its contents. the risk of using it lies entirelywith the user.