anchao commented on code in PR #7088: URL: https://github.com/apache/incubator-nuttx/pull/7088#discussion_r1000095259
########## include/sys/msg.h: ########## @@ -0,0 +1,212 @@ +/**************************************************************************** + * include/sys/msg.h + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance with the + * License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the + * License for the specific language governing permissions and limitations + * under the License. + * + ****************************************************************************/ + +#ifndef __INCLUDE_SYS_MSG_H +#define __INCLUDE_SYS_MSG_H + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> +#include <sys/ipc.h> +#include <time.h> + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +/* The MSG_NOERROR identifier value, the msqid_ds struct and the msg struct + * are as defined by the SV API Intel 386 Processor Supplement. + */ + +#define MSG_NOERROR 010000 /* No error if message is too big */ +#define MSG_EXCEPT 020000 /* Recv any msg except of specified type.*/ +#define MSG_COPY 040000 /* Copy (not remove) all queue messages */ + +/**************************************************************************** + * Public Type Declarations + ****************************************************************************/ + +typedef unsigned long msgqnum_t; +typedef unsigned long msglen_t; + +struct msqid_ds +{ + struct ipc_perm msg_perm; /* Ownership and permissions */ + time_t msg_stime; /* Time of last msgsnd(2) */ + time_t msg_rtime; /* Time of last msgrcv(2) */ + time_t msg_ctime; /* Time of last change */ + unsigned long msg_cbytes; /* Current number of bytes in + * queue (nonstandard) */ + msgqnum_t msg_qnum; /* Current number of messages + * in queue */ + msglen_t msg_qbytes; /* Maximum number of bytes + * allowed in queue */ + pid_t msg_lspid; /* PID of last msgsnd(2) */ + pid_t msg_lrpid; /* PID of last msgrcv(2) */ +}; + +/* Structure describing a message. The SVID doesn't suggest any + * particular name for this structure. There is a reference in the + * msgop man page that reads "The structure mymsg is an example of what + * this user defined buffer might look like, and includes the following + * members:". This sentence is followed by two lines equivalent + * to the mtype and mtext field declarations below. It isn't clear + * if "mymsg" refers to the name of the structure type or the name of an + * instance of the structure... + */ + +struct mymsg +{ + long mtype; /* message type (+ve integer) */ + char mtext[1]; /* message body */ +}; + +#ifdef __cplusplus +#define EXTERN extern "C" +extern "C" +{ +#else +#define EXTERN extern +#endif + +/**************************************************************************** + * Public Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Name: msgctl + * + * Description: + * System V message control operations. + * msgctl() performs the control operation specified by cmd on the + * System V message queue with identifier msqid. + * + * Input Parameters: + * msqid - System V message queue identifier + * cmd - Command operations + * msqid_ds - Defines a message queue + * + * Returned Value: + * On success, IPC_STAT, IPC_SET, and IPC_RMID return 0. A + * successful IPC_INFO or MSG_INFO operation returns the index of + * the highest used entry in the kernel's internal array recording + * information about all message queues. (This information can be + * used with repeated MSG_STAT or MSG_STAT_ANY operations to obtain + * information about all queues on the system.) A successful + * MSG_STAT or MSG_STAT_ANY operation returns the identifier of the + * queue whose index was given in msqid. + * + * On failure, -1 is returned and errno is set to indicate the error. + * + ****************************************************************************/ + +int msgctl(int msqid, int cmd, FAR struct msqid_ds *buf); + +/**************************************************************************** + * Name: msgget + * + * Description: + * Get a System V message queue identifier + * The msgget() system call returns the System V message queue + * identifier associated with the value of the key argument. It may + * be used either to obtain the identifier of a previously created + * message queue (when msgflg is zero and key does not have the + * value IPC_PRIVATE), or to create a new set. + * + * Input Parameters: + * key - Key associated with the message queue + * msgflg - Operations and permissions flag + * + * Returned Value: + * On success, msgget() returns the message queue identifier (a + * nonnegative integer). On failure, -1 is returned, and errno is + * set to indicate the error. + * + ****************************************************************************/ + +int msgget(key_t key, int msgflg); + +/**************************************************************************** + * Name: msgsnd + * + * Description: + * The msgsnd() function is used to send a message to the queue + * associated with the message queue identifier specified by msqid. + * The msgp argument points to a user-defined buffer that must contain + * first a field of type long int that will specify the type of the + * message, and then a data portion that will hold the data bytes of + * the message. + * + * Input Parameters: + * msqid - Message queue identifier + * msgp - Pointer to a buffer with the message to be sent + * msgsz - Length of the data part of the message to be sent + * msgflg - Operations flags + * + * Returned Value: + * On success, mq_send() returns 0 (OK); on error, -1 (ERROR) + * is returned, with errno set to indicate the error: + * + * EAGAIN The queue was full and the O_NONBLOCK flag was set for the + * message queue description referred to by mqdes. + * EINVAL Either msg or mqdes is NULL or the value of prio is invalid. + * EPERM Message queue opened not opened for writing. + * EMSGSIZE 'msglen' was greater than the maxmsgsize attribute of the + * message queue. + * EINTR The call was interrupted by a signal handler. + * + ****************************************************************************/ + +int msgsnd(int msqid, const void *msgp, size_t msgsz, int msgflg); Review Comment: Done -- This is an automated message from the Apache Git Service. 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