key_t 16 include/linux/ipc.h key_t key; key_t 653 include/linux/syscalls.h asmlinkage long sys_msgget(key_t key, int msgflg); key_t 660 include/linux/syscalls.h asmlinkage long sys_semget(key_t key, int nsems, int semflg); key_t 668 include/linux/syscalls.h asmlinkage long sys_shmget(key_t key, size_t size, int flag);