I want create a semaphore counter, with this code:
union semun arg_assistant;
int max_ass = atoi(argv[1]);
printf("Num massimo di assistant %d\n", max_ass);
fflush(stdout);
if ((sem_a = semget(IPC_PRIVATE, 1, 0600)) == -1) {
perror("semget");
exit(EXIT_FAILURE);
}
arg_assistant.val = max_ass;
if (semctl(sem_a, 0, SETALL, arg_assistant) == -1) {
perror("semctl");
exit(EXIT_FAILURE);
}
When I executed my program, I have no errors but it hangs and it don't create this sem. Any suggestion about what could be the problem? Have I make some mistake with falgs? Thaks
From documentation
SETALL
Set semval for all semaphores of the set using arg.array,
For SETALL
you need array of values
unsigned short int sem_array[1] ;
sem_array[0] = max_ass;
arg_assistant.array = sem_array;
if (semctl(sem_a, 0, SETALL, arg_assistant) == -1) {
perror("semctl");
exit(EXIT_FAILURE);
}
sem_array[1]
becaues you create only one semaphore.
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