On Dez 06 2017, Joakim Tjernlund [off-list ref] 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.
Andreas.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
On Wed, 2017-12-06 at 23:56 +0100, Andreas Schwab wrote:
=20
On Dez 06 2017, Joakim Tjernlund [off-list ref] wrote:
=20
quoted
st =3D semctl(sem, 0, IPC_STAT, &arg);
=20
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 wit=
h 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 =
=20
(Linux-specific) */
} semopts =3D {0};
semopts.buf =3D &arg;
#if defined(IPC_PRIVATE) && defined(S_IRWXU) && defined(S_IRWXG) && define=
d(S_IRWXO) && defined(IPC_CREAT)
sem =3D semget(IPC_PRIVATE, 1, S_IRWXU|S_IRWXG|S_IRWXO|IPC_CREAT);
if (sem > -1) {
#ifdef IPC_STAT
st =3D semctl(sem, 0, IPC_STAT, semopts);
if (st =3D=3D 0)
printf("semid_ds\n");
else
#endif /* IPC_STAT */
printf("semctl IPC_STAT failed: errno =3D %s\n", strerror(errno));
#ifdef IPC_RMID
if (semctl(sem, 0, IPC_RMID, semopts) !=3D 0)
#endif /* IPC_RMID */
printf("semctl IPC_RMID failed: errno =3D %d\n", errno);
} else
#endif /* IPC_PRIVATE && ... */
printf("semget failed: errno =3D %d\n", errno);
return 0;
Jocke=