StuBS
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Semaphore used for synchronization of threads. More...
#include <sync/semaphore.h>
Public Member Functions | |
Semaphore (unsigned c=0) | |
Constructor; initialized the counter with provided value c More... | |
void | p () |
Wait for access to the critical area. More... | |
void | v () |
Leave the critical area. More... | |
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Waitingroom () | |
Constructor. More... | |
virtual | ~Waitingroom () |
Destructor. More... | |
virtual void | remove (Thread *customer) |
Remove a given thread prematurely from the Waitingroom. More... | |
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Queue () | |
Default constructor; initialized the queue as empty. | |
void | enqueue (Thread *item) |
Enqueues the provided item at the end of the queue. More... | |
Thread * | dequeue () |
Removes the first element in the queue and returns it. More... | |
Iterator | begin () |
Iterator | end () |
Thread * | remove (Thread *item, bool(*cmp)(Thread *, Thread *)=[](Thread *a, Thread *b) {return a==b;}) |
Removes and returns a single element from the queue. More... | |
void | insertFirst (Thread *item) |
Adds item to the beginning of the queue. More... | |
void | insertAfter (Thread *old_item, Thread *new_item) |
Inserts the element new_item directly after old_item . More... | |
Thread * | first () |
Returns the first element in the queue without removing it. More... | |
Thread * | next (Thread *o) |
Returns the next element in the queue for a given element. | |
Semaphore used for synchronization of threads.
The class Semaphore implements the concept of counting semaphores. The waiting list is provided by the base class Waitingroom.
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inlineexplicit |
Constructor; initialized the counter with provided value c
c | Initial counter value |
void Semaphore::p | ( | ) |
Wait for access to the critical area.
Enter/Wait operation: If the counter is greater than 0, then it is decremented by one. Otherwise the calling thread will be enqueued into the Waitingroom and marked as blocked.
void Semaphore::v | ( | ) |
Leave the critical area.
Leave operation: If there are threads in the Waitingroom, wake the first one; otherwise increment the counter by one.