Question

I am working on a project that creates two processes and I want to regulate the IPC between them.

The processes are created with the createProces function, and I want to use a mutex to do some IPC.

In Linux I do this with semaphores, however I have read that for IPC in Windows I have to use a mutex.

In windows I can’t seem to get it to work. First I create the treads like this:

CreateProcess(IpApplicationName, NULL, NULL, NULL, FALSE,   CREATE_NEW_CONSOLE, NULL, NULL,     &StartInfo, &ProcessInfo);
CreateProcess(IpApplicationName, NULL, NULL, NULL, FALSE,   CREATE_NEW_CONSOLE, NULL, NULL,     &StartInfo2, &ProcessInfo2);

The processes start up normal but when I remove the releaseMutex call from one process it won’t be kept waiting in that process. Here is process one:

volatile HANDLE hMutex; // Global hMutex Object


int main()
{
     hMutex=CreateMutex(NULL,FALSE,NULL);

    while(1)
    {

        WaitForSingleObject(hMutex,INFINITE);
        printf("Thread writing to database...\n");
        Sleep(2000);
        ReleaseMutex(hMutex);
    }

    return 0;
 }

In process two I open the mutex with open mutex and comment the releaseMutex (so that it will be stuck here, for testing. However it will keep on going):

int main()
{

 while(1)
 {
    HANDLE hMutex;

    hMutex=OpenMutex(MUTEX_ALL_ACCESS,FALSE,MUTEXNAME);

    WaitForSingleObject(hMutex,INFINITE);
    printf("Thread writing to database22...\n");
    Sleep(2000);
    //ReleaseMutex(hMutex);
 }

    return 0;
}

Can anyone tell me what I am doing wrong?

Answer 1

You create anonymous Mutex using CreateMutex, then try to find it by name