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#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <errno.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#ifdef _SEM_SEMUN_UNDEFINED
union semun {
int val;
struct semid_ds *buf;
unsigned short *array;
};
#endif
char *argv0;
int main(int argc, char *argv[])
{
key_t key;
int id = -1;
(void) argc;
argv0 = *argv;
srand(time(NULL));
for (;;) {
double r = (double)rand();
r /= (double)RAND_MAX + 1;
r *= (1 << (8 * sizeof(key_t) - 2)) - 1;
key = (key_t)r + 1;
if (key == IPC_PRIVATE)
continue;
id = semget(key, 3, IPC_CREAT | IPC_EXCL | 0600);
if (id != -1)
break;
if ((errno != EEXIST) && (errno != EINTR))
goto fail;
}
printf("key:%zx, id:%i\n", (size_t)key, id);
if (semctl(id, 0, IPC_RMID) == -1)
goto fail;
return 0;
fail:
perror(argv0);
if ((id != -1) && (semctl(id, 0, IPC_RMID) == -1))
perror(argv0);
return 1;
}
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