C++ 多进程学习总结

C++多进程

进程间通信

消息队列

消息队列：提供一个种进程间发送/接收数据块（常为结构体数据）的方法。

函数接口

ftok()：获取消息队列键值
msgget()：创建和访问消息队列
msgsnd()：向消息队列发送数据
msgrcv()：从消息队列接收数据
msgctl()：设置消息队列属性

示例

hpp

#define MSG_PATHNAME	"/tmp"	//系统任意存在的路径名
#define MSG_PROJ		(234)	//1~255任一数字typedef struct _msgSt {int msgType;char msgData[32];
} MsgSt;class IpcMsg
{
public:IpcMsg() {};~IpcMsg() {};int msgInit(){/* 生成key值 */m_msgKey = ftok(MSG_PATHNAME, MSG_PROJ);if (-1 == m_msgKey) {cout << "ftok msgKey error" << endl;return -1;}/*建立消息队列*/m_msgId = msgget(m_msgKey, 0666 | IPC_CREAT);if (-1 == m_msgId) {cout << "msg creat error" << endl;return -1;}return 0;}int msgSend(char *msgBuf, int msgSize){int ret = msgsnd(m_msgId, msgBuf, msgSize, 0);if (ret < 0) {cout << "msgsnd error" << endl;return -1;}return 0;}int msgRecv(char *msgBuf, int msgSize) {int ret = msgrcv(m_msgId, msgBuf, msgSize, 0, 0);if (ret < 0) {cout << "msgrcv error" << endl;return -1;}return ret;}void msgDeinit() {msgctl(m_msgId, IPC_RMID, NULL);}
private:key_t m_msgKey = -1;int m_msgId = -1;
};

cpp

void custom_ipc_msg_process_task(char* argv[]){if (nullptr == argv[1]) {cout << "argv[1] is nullptr" << endl;}string cmd = argv[1];cout << "cmd: " << cmd << endl;IpcMsg ipcMsg;/* 初始化msg */int ret = ipcMsg.msgInit();if (ret < 0) {cout << "msgInit error" << endl;return ;}if (0 == cmd.compare("msgsnd")) {MsgSt msgBuf;while(1){memset(&msgBuf, 0, sizeof(msgBuf));msgBuf.msgType = 1;strncpy(msgBuf.msgData, "msg test", strlen("msg test"));int ret = ipcMsg.msgSend((char *) & msgBuf, (int)sizeof(msgBuf));if (ret < 0) {cout << "msgSend error" << endl;}else {cout << "msgSend ok :" << msgBuf.msgType <<", " <<msgBuf.msgData<< endl;}sleep(3);}}else if (0 == cmd.compare("msgrcv")) {char recvBuf[128];while (1) {memset(recvBuf, 0, sizeof(recvBuf));int ret = ipcMsg.msgRecv(recvBuf, sizeof(recvBuf));if (ret < 0) {cout << "msgrcv error" << endl;}else if(ret == sizeof(MsgSt)) {MsgSt *msgBuf = (MsgSt *)recvBuf;cout << "msgrcv: " << msgBuf->msgType<<", " <<msgBuf->msgData<< endl;}else{cout << "msgrcv size error" << endl;}}}else {cout << "invalid cmd" << endl;}/* 去初始化msg */ipcMsg.msgDeinit();return;
}