DisastrOS_semaphores implementation for SO course.
List of system calls added in DisastrOS:
int DisastrOS_semOpen(int semnum)Creates a semaphore in the system, identified by id semnum and become accessible throughout it.
On success, the function call returns a non negative integer. On failure the function returns an error code (with a negative value),defined in disastrOS_constants.h:
-DSOS_ESEMID (-14) : negative id
-DSOS_ESEMDESC (-15) : invalid semDescriptor
-DSOS_ESEMALLOC (-16) : failed to allocate the semDescriptor
int DisastrOS_semClose(int semnum)Close a semaphore referred by semnum, releasing the resources.
Returns 0 on success or an error code (negative value) in case of failure:
-DSOS_ESEMID (-14) : negative id
-DSOS_ESEMDESC (-15) : invalid semDescriptor
-DSOS_ENOSEM (-17) : Semaphore not found
int DisastrOS_semWait(int semnum);Takes the semaphore by id and decrements it's counter.
If is <= 0, the caller is put into the wait queue.
Returns 0 on success or an error code (negative value) in case of failure:
-DSOS_ESEMID (-14) : negative id
-DSOS_ESEMDESC (-15) : invalid semDescriptor
int DisastrOS_semPost(int semnum);Takes the semaphore by id and increments it's counter.
if the semaphore was at 0, and some other thread was waiting,
the thread is resumed.
Returns 0 on success or an error code (negative value) in case of failure:
-DSOS_ESEMID (-14) : negative id
-DSOS_ESEMDESC (-15) : invalid semDescriptor
To compile do
make
then ./disastrOS_test
to run the test.
To check memory leaks:
valgrind ./disastrOS_test