Enrico Fraccaroli
126 lines
5.0 KiB
C
126 lines
5.0 KiB
C
/// @file msg.h
|
|
/// @brief Definition of structure for managing message queues.
|
|
/// @copyright (c) 2014-2022 This file is distributed under the MIT License.
|
|
/// See LICENSE.md for details.
|
|
|
|
#pragma once
|
|
|
|
#include "sys/types.h"
|
|
#include "stddef.h"
|
|
#include "time.h"
|
|
#include "ipc.h"
|
|
|
|
/// Type for storing the number of messages in a message queue.
|
|
typedef unsigned int msgqnum_t;
|
|
|
|
/// Type for storing the number of bytes in a message queue.
|
|
typedef unsigned int msglen_t;
|
|
|
|
/// @brief Buffer to use with the message queue IPC.
|
|
typedef struct msgbuf {
|
|
/// Type of the message.
|
|
long mtype;
|
|
/// Text of the message.
|
|
char mtext[1];
|
|
} msgbuf_t;
|
|
|
|
/// @brief Message queue data structure.
|
|
typedef struct msqid_ds {
|
|
/// Ownership and permissions.
|
|
struct ipc_perm msg_perm;
|
|
/// Time of last msgsnd(2).
|
|
time_t msg_stime;
|
|
/// Time of last msgrcv(2).
|
|
time_t msg_rtime;
|
|
/// Time of creation or last modification by msgctl().
|
|
time_t msg_ctime;
|
|
/// Number of bytes in queue.
|
|
unsigned long msg_cbytes;
|
|
/// Number of messages in queue.
|
|
msgqnum_t msg_qnum;
|
|
/// Maximum number of bytes in queue.
|
|
msglen_t msg_qbytes;
|
|
/// PID of last msgsnd(2).
|
|
pid_t msg_lspid;
|
|
/// PID of last msgrcv(2).
|
|
pid_t msg_lrpid;
|
|
} msqid_ds_t;
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
/// @brief Get a System V message queue identifier.
|
|
/// @param key can be used either to obtain the identifier of a previously
|
|
/// created message queue, or to create a new set.
|
|
/// @param msgflg controls the behaviour of the function.
|
|
/// @return the message queue identifier, -1 on failure, and errno is set to
|
|
/// indicate the error.
|
|
long sys_msgget(key_t key, int msgflg);
|
|
|
|
/// @brief Used to send messages.
|
|
/// @param msqid the message queue identifier.
|
|
/// @param msgp points to a used-defined msgbuf.
|
|
/// @param msgsz specifies the size in bytes of mtext.
|
|
/// @param msgflg specifies the action to be taken in case of specific events.
|
|
/// @return 0 on success, -1 on failure and errno is set to indicate the error.
|
|
long sys_msgsnd(int msqid, msgbuf_t *msgp, size_t msgsz, int msgflg);
|
|
|
|
/// @brief Used to receive messages.
|
|
/// @param msqid the message queue identifier.
|
|
/// @param msgp points to a used-defined msgbuf.
|
|
/// @param msgsz specifies the size in bytes of mtext.
|
|
/// @param msgtyp specifies the type of message requested, as follows:
|
|
/// - msgtyp == 0: the first message on the queue is received.
|
|
/// - msgtyp > 0: the first message of type, msgtyp, is received.
|
|
/// - msgtyp < 0: the first message of the lowest type that is less than or
|
|
/// equal to the absolute value of msgtyp is received.
|
|
/// @param msgflg specifies the action to be taken in case of specific events.
|
|
/// @return 0 on success, -1 on failure and errno is set to indicate the error.
|
|
long sys_msgrcv(int msqid, msgbuf_t *msgp, size_t msgsz, long msgtyp, int msgflg);
|
|
|
|
/// @brief Message queue control operations.
|
|
/// @param msqid the message queue identifier.
|
|
/// @param cmd The command to perform.
|
|
/// @param buf used with IPC_STAT and IPC_SET.
|
|
/// @return 0 on success, -1 on failure and errno is set to indicate the error.
|
|
long sys_msgctl(int msqid, int cmd, msqid_ds_t *buf);
|
|
|
|
#else
|
|
|
|
/// @brief Get a System V message queue identifier.
|
|
/// @param key can be used either to obtain the identifier of a previously
|
|
/// created message queue, or to create a new set.
|
|
/// @param msgflg controls the behaviour of the function.
|
|
/// @return the message queue identifier, -1 on failure, and errno is set to
|
|
/// indicate the error.
|
|
long msgget(key_t key, int msgflg);
|
|
|
|
/// @brief Used to send messages.
|
|
/// @param msqid the message queue identifier.
|
|
/// @param msgp points to a used-defined msgbuf.
|
|
/// @param msgsz specifies the size in bytes of mtext.
|
|
/// @param msgflg specifies the action to be taken in case of specific events.
|
|
/// @return 0 on success, -1 on failure and errno is set to indicate the error.
|
|
long msgsnd(int msqid, msgbuf_t *msgp, size_t msgsz, int msgflg);
|
|
|
|
/// @brief Used to receive messages.
|
|
/// @param msqid the message queue identifier.
|
|
/// @param msgp points to a used-defined msgbuf.
|
|
/// @param msgsz specifies the size in bytes of mtext.
|
|
/// @param msgtyp specifies the type of message requested, as follows:
|
|
/// - msgtyp == 0: the first message on the queue is received.
|
|
/// - msgtyp > 0: the first message of type, msgtyp, is received.
|
|
/// - msgtyp < 0: the first message of the lowest type that is less than or
|
|
/// equal to the absolute value of msgtyp is received.
|
|
/// @param msgflg specifies the action to be taken in case of specific events.
|
|
/// @return 0 on success, -1 on failure and errno is set to indicate the error.
|
|
long msgrcv(int msqid, msgbuf_t *msgp, size_t msgsz, long msgtyp, int msgflg);
|
|
|
|
/// @brief Message queue control operations.
|
|
/// @param msqid the message queue identifier.
|
|
/// @param cmd The command to perform.
|
|
/// @param buf used with IPC_STAT and IPC_SET.
|
|
/// @return 0 on success, -1 on failure and errno is set to indicate the error.
|
|
long msgctl(int msqid, int cmd, msqid_ds_t *buf);
|
|
|
|
#endif
|