sys/msg.h - message queue structures
The <sys/msg.h> header defines the following constant and members of the structure msqid_ds.
The following data types are defined through typedef:
Used for the number of messages in the message queue.
Used for the number of bytes allowed in a message queue.
These types are unsigned integer types that are able to store values at least as large as a type unsigned short.
Message operation flag:
- No error if big message.
The structure msqid_ds contains the following members:
struct ipc_perm msg_perm operation permission structure msgqnum_t msg_qnum number of messages currently on queue msglen_t msg_qbytes maximum number of bytes allowed on queue pid_t msg_lspid process ID of last msgsnd() pid_t msg_lrpid process ID of last msgrcv() time_t msg_stime time of last msgsnd() time_t msg_rtime time of last msgrcv() time_t msg_ctime time of last change
The pid_t, time_t, key_t and size_t types are defined as described in <sys/types.h>.
The following are declared as functions and may also be defined as macros. Function prototypes must be provided for use with an ISO C compiler.
int msgctl(int, int, struct msqid_ds *); int msgget(key_t, int); ssize_t msgrcv(int, void *, size_t, long int, int); int msgsnd(int, const void *, size_t, int);
In addition, all of the symbols from <sys/ipc.h> will be defined when this header is included.
msgctl(), msgget(), msgrcv(), msgsnd(), <sys/types.h>.