为了实现自己的消息队列小小观摩了一下内核代码

wsm

不过那个结构msg_queue是干什么用的？
和msqid_ds类似但是不全阿

Dragonfly

message queue header?

wsm

struct msqid_ds {
        struct ipc_perm msg_perm;
        struct msg *msg_first;                /* first message on queue,unused  */
        struct msg *msg_last;                /* last message in queue,unused */
        __kernel_time_t msg_stime;        /* last msgsnd time */
        __kernel_time_t msg_rtime;        /* last msgrcv time */
        __kernel_time_t msg_ctime;        /* last change time */
        unsigned long  msg_lcbytes;        /* Reuse junk fields for 32 bit */
        unsigned long  msg_lqbytes;        /* ditto */
        unsigned short msg_cbytes;        /* current number of bytes on queue */
        unsigned short msg_qnum;        /* number of messages in queue */
        unsigned short msg_qbytes;        /* max number of bytes on queue */
        __kernel_ipc_pid_t msg_lspid;        /* pid of last msgsnd */
        __kernel_ipc_pid_t msg_lrpid;        /* last receive pid */
};
这个是在msg.h里的结构，看上去比较合乎我本来的构思（比如有起始指针结束指针）
但是它的注释是：/* Obsolete, used only for backwards compatibility and libc5 compiles */

新的结构是
struct msg_queue {
        struct kern_ipc_perm q_perm;
        time_t q_stime;                        /* last msgsnd time */
        time_t q_rtime;                        /* last msgrcv time */
        time_t q_ctime;                        /* last change time */
        unsigned long q_cbytes;                /* current number of bytes on queue */
        unsigned long q_qnum;                /* number of messages in queue */
        unsigned long q_qbytes;                /* max number of bytes on queue */
        pid_t q_lspid;                        /* pid of last msgsnd */
        pid_t q_lrpid;                        /* last receive pid */

        struct list_head q_messages;
        struct list_head q_receivers;
        struct list_head q_senders;
};
在msg.c中 看来具体的队列被分开了阿

呵呵 我还是按照旧的结构做比较适合

Dragonfly

yes, divided to three lists, so shoudl be faster for large link
and the start pointer and end pointer can be easily getten from list_head