c++-ReleaseMutex在错误的时间和程序不同步winapi

Drake Wu 2020-12-01 11:15:37

你不能使用互斥锁来同步这两个过程。由program1释放的互斥锁可以再次由program1捕获。

每次我运行它时，program1都会写入文件映射中的所有内容，并且在运行每个实例之后，program2仅读取文件映射中写入的最后一个数字。

可能是program1发行版的互斥锁始终由program1本身捕获（100次），然后由program2捕获。一个进程需要通知另一进程它已经完成了读写（使用IPC）。你可以创建2个事件，然后使用它来通知每个进程中的另一个进程。

程序1：

#include <iostream>
#include <Windows.h>
#include <time.h>
using namespace std;

struct RandomSum {
    DWORD a;
    DWORD b;
};


int main()
{
    //srand((unsigned int)time(NULL));
    cout << "inside process 1" << endl;

    HANDLE hEvent1 = CreateEvent(NULL, FALSE, TRUE, "MyEvent1");
    HANDLE hEvent2 = CreateEvent(NULL, FALSE, FALSE, "MyEvent2");

    HANDLE create_file_mapping_handle = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE,
        0, 1024 * 1024, "data");
    if (create_file_mapping_handle == NULL) {
        printf("Cannot create file mapping. Error code: %d", GetLastError());
        return 0;
    }

    unsigned char* pData = (unsigned char*)MapViewOfFile(create_file_mapping_handle,
        FILE_MAP_ALL_ACCESS, 0, 0, 0);
    if (pData == NULL) {
        printf("Cannot get pointer to file mapping. Error code: %d", GetLastError());
        CloseHandle(create_file_mapping_handle);
        return 0;
    }

    //create new process
    PROCESS_INFORMATION process2;
    STARTUPINFO si;
    memset(&si, 0, sizeof(si));
    si.cb = sizeof(si);
    if (!CreateProcess("C:\\path\\program2.exe", NULL,
        NULL, NULL, FALSE, 0, NULL, NULL, &si, &process2)) {
        printf("Cannot create process.\n");
        return 0;
    }
    CloseHandle(process2.hThread);
    CloseHandle(process2.hProcess);    
    int counter = 0;
    while (counter < 100) {
        DWORD dwWaitResult = WaitForSingleObject(
            hEvent1,    // handle to mutex
            INFINITE);  // no time-out interval

        if (dwWaitResult == WAIT_OBJECT_0) {
            cout << "am intrat in sender process si scriu in file mapping" << endl;
            RandomSum test;

            DWORD randomNumber = rand() % 50;
            test.a = randomNumber;
            test.b = 2 * test.a;
            memcpy(pData, &test, sizeof(RandomSum));
            cout << "in process 1: " << "a = " << test.a << " b= " << test.b << endl;
            cout << "last cout" << endl;
            SetEvent(hEvent2);
        }

        ++counter;
    }
    UnmapViewOfFile(pData);
    CloseHandle(create_file_mapping_handle);
    CloseHandle(hEvent1);
    CloseHandle(hEvent2);
    //getchar();
    return 0;
}

程序2：

#include <iostream>
#include <Windows.h>
#include <time.h>
using namespace std;

struct RandomSum {
    DWORD a;
    DWORD b;
};

int main()
{
    cout << "inside process2" << endl;
    //srand((unsigned int)time(NULL));

    cout << "something new in process2" << endl;
    HANDLE hEvent1 = OpenEvent(EVENT_MODIFY_STATE | SYNCHRONIZE, FALSE, "MyEvent1");
    HANDLE hEvent2 = OpenEvent(EVENT_MODIFY_STATE | SYNCHRONIZE, FALSE, "MyEvent2");

    LPCWSTR data = L"data";
    HANDLE hData = OpenFileMapping(FILE_MAP_ALL_ACCESS, FALSE, "data");

    unsigned char* pData = (unsigned char*)MapViewOfFile(hData, FILE_MAP_ALL_ACCESS, 0, 0, 0);
    if (pData == NULL) {
        printf("Cannot get pointer to file mapping. Error code: %d", GetLastError());
        CloseHandle(hData);
        return 0;
    }

    int counter = 0;
    while (counter < 100) {
        DWORD dwWaitResult = WaitForSingleObject(
            hEvent2,    // handle to mutex
            INFINITE);  // no time-out interval
        if (dwWaitResult == WAIT_OBJECT_0) {
            cout << "a inceput procesul 2" << endl;
            RandomSum test;

            memcpy(&test, pData, sizeof(RandomSum));

            cout << "a is " << test.a << " and b is " << test.b << endl;
            SetEvent(hEvent1);
        }
        ++counter;

    }
    UnmapViewOfFile(pData);
    CloseHandle(hData);
    CloseHandle(hEvent1);
    CloseHandle(hEvent2);
    //getchar();
}

或者直接使用你用于同步的共享内存。使用的第一个字节pdata作为信号位，每个进程监视是否轮到该执行。

程序1：

#include <iostream>
#include <Windows.h>
#include <time.h>
using namespace std;

struct RandomSum {
    DWORD a;
    DWORD b;
};
BOOL WaitForProcess2(unsigned char* shared_address)
{
    while (*shared_address != 1);//wait until the process1 set the first byte to 1;
    return true;
}

int main()
{
    //srand((unsigned int)time(NULL));
    cout << "inside process 1" << endl;


    HANDLE create_file_mapping_handle = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE,
        0, 1024 * 1024, "data");
    if (create_file_mapping_handle == NULL) {
        printf("Cannot create file mapping. Error code: %d", GetLastError());
        return 0;
    }

    unsigned char* pData = (unsigned char*)MapViewOfFile(create_file_mapping_handle,
        FILE_MAP_ALL_ACCESS, 0, 0, 0);
    if (pData == NULL) {
        printf("Cannot get pointer to file mapping. Error code: %d", GetLastError());
        CloseHandle(create_file_mapping_handle);
        return 0;
    }
    *pData = 1;
    //create new process
    PROCESS_INFORMATION process2;
    STARTUPINFO si;
    memset(&si, 0, sizeof(si));
    si.cb = sizeof(si);
    if (!CreateProcess("C:\\path\\program2.exe", NULL,
        NULL, NULL, FALSE, 0, NULL, NULL, &si, &process2)) {
        printf("Cannot create process.\n");
        return 0;
    }
    CloseHandle(process2.hThread);
    CloseHandle(process2.hProcess);
    int counter = 0;
    while (counter < 100) {
        if (WaitForProcess2(pData)) {
            cout << "am intrat in sender process si scriu in file mapping" << endl;
            RandomSum test;

            DWORD randomNumber = rand() % 50;
            test.a = randomNumber;
            test.b = 2 * test.a;
            memcpy(pData+1, &test, sizeof(RandomSum)); //"pData + 1" skip the first signal bit
            cout << "in process 1: " << "a = " << test.a << " b= " << test.b << endl;
            cout << "last cout" << endl;
            *pData = 2;
        }
        ++counter;
    }
    UnmapViewOfFile(pData);
    CloseHandle(create_file_mapping_handle);
    //getchar();
    return 0;
}

程序2：

#include <iostream>
#include <Windows.h>
#include <time.h>
using namespace std;

struct RandomSum {
    DWORD a;
    DWORD b;
};
BOOL WaitForProcess1(unsigned char* shared_address)
{
    while (*shared_address != 2); //wait until the process1 set the first byte to 2;
    return true;
}
int main()
{
    cout << "inside process2" << endl;
    //srand((unsigned int)time(NULL));

    cout << "something new in process2" << endl;

    LPCWSTR data = L"data";
    HANDLE hData = OpenFileMapping(FILE_MAP_ALL_ACCESS, FALSE, "data");

    unsigned char* pData = (unsigned char*)MapViewOfFile(hData, FILE_MAP_ALL_ACCESS, 0, 0, 0);
    if (pData == NULL) {
        printf("Cannot get pointer to file mapping. Error code: %d", GetLastError());
        CloseHandle(hData);
        return 0;
    }

    int counter = 0;
    while (counter < 100) {

        if (WaitForProcess1(pData)) {
            cout << "a inceput procesul 2" << endl;
            RandomSum test;

            memcpy(&test, pData + 1, sizeof(RandomSum)); //"pData + 1" skip the first signal bit

            cout << "a is " << test.a << " and b is " << test.b << endl;
            *pData = 1;
        }
        ++counter;

    }
    UnmapViewOfFile(pData);
    CloseHandle(hData);

    //getchar();
}

JohnMat 2020-12-02 21:57:34

最后，正如您向我展示的那样，我使用了事件。非常感谢你！整个问题现在对我来说很清楚。

c++-ReleaseMutex在错误的时间和程序不同步winapi

(c++ - ReleaseMutex at the wrong time and the programs don't synchronize winapi)

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