48、Solaris 系统中的进程间通信：信号量与消息队列详解

Solaris 系统中的进程间通信：信号量与消息队列详解

1. Solaris 中的信号量操作

在 Solaris 系统里，应用程序创建信号量集需要调用semget(2)函数。系统中每个信号量集都由semid_ds数据结构来描述，该结构包含以下元素：

/* * There is one semaphore id data structure (semid_ds) for each set of * semaphores in the system. */ struct semid_ds { struct ipc_perm sem_perm; /* operation permission struct */ struct sem *sem_base; /* ptr to first semaphore in set */ ushort_t sem_nsems; /* # of semaphores in set */ time_t sem_otime; /* last semop time */ long sem_pad1; /* reserved for time_t expansion */ time_t sem_ctime; /* last change time */ long sem_pad