The previous section focused on affecting changes in the semaphore and set attributes, and on obtaining information. This section will cover the aspects of using semaphores to perform the following:
Wait for zero operations
These operations work on the entire set of semaphores or on a subset. You can also operate on individual semaphores in the set according to your application needs.
Semaphore operations are performed by the semop(2) system call. Its function synopsis is as follows:
#include <sys/types.h> #include <sys/ipc.h> #include <sys/sem.h> int semop(int semid, struct sembuf array, unsigned nops);
The argument semid contains the IPC ID of the semaphore set, which is returned by the ...