On Wed, 2017-12-06 at 23:56 +0100, Andreas Schwab wrote:
>
> On Dez 06 2017, Joakim Tjernlund <joakim.tjernl...@infinera.com> wrote:
>
> > st = semctl(sem, 0, IPC_STAT, &arg);
>
> This is not a valid use of IPC_STAT. The fourth argument must be a
> object of type union semun (not a pointer), with the .buf member
> pointing to the struct semid_ds object.
Ahh, so perl had it wrong (Any perl guys here?). This is what I came up with
and it works:
struct semid_ds arg;
union semun {
int val; /* Value for SETVAL */
struct semid_ds *buf; /* Buffer for IPC_STAT, IPC_SET */
unsigned short *array; /* Array for GETALL, SETALL */
struct seminfo *__buf; /* Buffer for IPC_INFO
(Linux-specific) */
} semopts = {0};
semopts.buf = &arg;
#if defined(IPC_PRIVATE) && defined(S_IRWXU) && defined(S_IRWXG) &&
defined(S_IRWXO) && defined(IPC_CREAT)
sem = semget(IPC_PRIVATE, 1, S_IRWXU|S_IRWXG|S_IRWXO|IPC_CREAT);
if (sem > -1) {
#ifdef IPC_STAT
st = semctl(sem, 0, IPC_STAT, semopts);
if (st == 0)
printf("semid_ds\n");
else
#endif /* IPC_STAT */
printf("semctl IPC_STAT failed: errno = %s\n", strerror(errno));
#ifdef IPC_RMID
if (semctl(sem, 0, IPC_RMID, semopts) != 0)
#endif /* IPC_RMID */
printf("semctl IPC_RMID failed: errno = %d\n", errno);
} else
#endif /* IPC_PRIVATE && ... */
printf("semget failed: errno = %d\n", errno);
return 0;
Jocke
