Windows系統——多進程多線程任務隊列管理（進程通信）（臨界資源訪問）

Windows系統——多進程多線程任務隊列管理（進程通信）（臨界資源訪問）

相關知識

Windows系統——進程通信共享內存區
Windows系統——進程創建
Windows系統——多線程互斥訪問臨界資源
Windows系統——線程創建

實現代碼

• Printer.cpp

/*
author : eclipse
email  : [email protected]
time   : Sun Apr 26 12:44:13 2020
*/
#include <bits/stdc++.h>
#include <windows.h>
#include "Queue.cpp"
using namespace std;

//queue<string> q;
Queue q;
const int BUFFER_SIZE = 1024;
const char shareMemory[] = "task";
CRITICAL_SECTION mutex;
char *buffer = NULL;

DWORD CALLBACK read(LPVOID param) {
    while (true) {
        if (buffer[0]) {
            EnterCriticalSection(&mutex);
            string t = string(buffer);
            q.push(t);
            LeaveCriticalSection(&mutex);
            if (!strcmp(buffer, "finish")) {
                break;
            }
            buffer[0] = '\0';
        }
    }
    return 0;
}


int main(int argc, char const *argv[])
{
    InitializeCriticalSection(&mutex);

    HANDLE mappingFileHandle;
    if (!(mappingFileHandle = CreateFileMapping(
        INVALID_HANDLE_VALUE,
        NULL,
        PAGE_READWRITE,
        0,
        BUFFER_SIZE,
        shareMemory))) {
        printf("Create file mapping error(%d)!", GetLastError());
        abort();
    }

    if (!(buffer = (char *)MapViewOfFile(
		mappingFileHandle,
        FILE_MAP_ALL_ACCESS,
        0,
        0,
        BUFFER_SIZE))) {
        printf("Map file error(%d)", GetLastError());
        abort();
    }
    
    HANDLE readThreadHandle = NULL;
    DWORD readThreadId;
    if (!(readThreadHandle = CreateThread(NULL, 0, read, NULL, 0, &readThreadId))) {
        printf("Thread create error(%d)\n", GetLastError());
        abort();
    }

    while (q.empty() || q.front() != "finish") {
        if (!q.empty() && q.front() != "finish") {
            printf("Received data\n");
            printf("Ready to print\n");
            printf("Printing [");
            for (int i = 0; i < 10; i++) {
                Sleep(200);
                printf("=");
            }
            printf("]\n");
            EnterCriticalSection(&mutex);
            cout << q.front() << endl;
            q.pop();
            LeaveCriticalSection(&mutex);
            printf("\07Print successfully\n");
        }
    }
    
    DeleteCriticalSection(&mutex);
	UnmapViewOfFile(buffer);
    CloseHandle(mappingFileHandle);
	return 0;
}

• Writer.cpp

/*
author : eclipse
email  : [email protected]
time   : Sun Apr 26 12:44:13 2020
*/
#include<bits/stdc++.h>
#include<windows.h>
using namespace std;

const int BUFFER_SIZE = 1024;
const char shareMemory[] = "task";

int main(int argc, char const *argv[])
{
    STARTUPINFO si;
    PROCESS_INFORMATION pi;

    ZeroMemory(&si, sizeof(si));

    si.cb = sizeof(si);

    ZeroMemory(&pi, sizeof(pi));

    if (!CreateProcess(NULL,
        (LPSTR) "printer.exe",
        NULL,
        NULL,
        FALSE,
        CREATE_NEW_CONSOLE,
        NULL,
        NULL,
        &si,
        &pi)) {
        printf("Create Process error(%d)!\n", GetLastError());
        abort();
    }

    HANDLE mappingFileHandle;

    if (!(mappingFileHandle = CreateFileMapping(
        INVALID_HANDLE_VALUE,
        NULL,
        PAGE_READWRITE,
        0,
        BUFFER_SIZE,
        shareMemory))) {
        printf("Create file mapping error(%d)!", GetLastError());
        abort();
    }
 
 
    char *buffer = NULL;

    if (!(buffer = (char*) MapViewOfFile(
		mappingFileHandle,
        FILE_MAP_ALL_ACCESS,
        0,
        0,
        BUFFER_SIZE
    ))) {
        printf("Map file error(%d)\n", GetLastError());
        abort();
    }

    while (strcmp(buffer, "finish")) {
        printf("Send data\n");
        gets(buffer);
    }
 
	UnmapViewOfFile(buffer);
    CloseHandle(mappingFileHandle);
	return 0;
}

• Queue.cpp

/*
author : eclipse
email  : [email protected]
time   : Sun Apr 26 14:46:53 2020
*/

#include<bits/stdc++.h>
using namespace std;
typedef string ElemType;

const int MAXSIZE = 1000;

struct Queue
{
    ElemType data[MAXSIZE];
    int frontPointer;
    int rearPointer;
    bool tag;
    ElemType front();
    void pop();
    void push(ElemType x);
    bool empty();
    bool full();
    Queue() : frontPointer(0), rearPointer(0), tag(false) {}
};

ElemType Queue::front() {
    return empty() ? "-1" : data[frontPointer]; 
}

void Queue::pop() {
    if (empty()) {
        printf("The queue is empty!\n");
        return;
    }
    frontPointer = (frontPointer + 1) % MAXSIZE;
    if (frontPointer == rearPointer) {
        tag = false;
    }
}

void Queue::push(ElemType x) {
    if (full()) {
        printf("The queue is full!\n");
        return;
    }
    data[rearPointer] = x;
    rearPointer = (rearPointer + 1) % MAXSIZE;
    if (rearPointer == frontPointer) {
        tag = true;
    }
}

bool Queue::empty() {
    return frontPointer == rearPointer && !tag;
}

bool Queue::full() {
    return frontPointer == rearPointer && tag;
}

實現

• 效果
  從Writer進程輸入數據，Writer進程創建子進程Printer，子進程主線程創建子線程從內存區讀取數據進入等待隊列，子進程Printer主線程從隊列取隊首元素異步地輸出數據（間隔兩秒打印一次數據）
• 思路
  上述實現借用兩個進程，父進程輸入，子進程藉助兩個線程，一個線程讀取共享內存區的數據，主線程每個兩秒相對於子線程異步地打印數據， 上述實現中的隊列是自行編寫的，將Queue q;改成queue<string> q;即可使用STL隊列
• 互斥訪問隊列
  子進程Printer主線程和子線程互斥地進入臨界區訪問共享全局變量隊列q，子線程等待輸入，主線程打印結果
• 進程通信共享內存區
  進程Writer和子進程Printer通過共享內存區進行進程間通信，父進程輸入數據進入共享內存區，子進程子線程從共享內存區讀取數據，父進程輸出數據到控制檯

編譯過程

g++ Printer.cpp -o printer
g++ Writer.cpp -o writer
writer.exe

效果截圖

最後

• 由於博主水平有限，不免有疏漏之處，歡迎讀者隨時批評指正，以免造成不必要的誤解