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I'm trying to compress a file consisting of 1's and 0's as part of an assignment. I have succeeded in doing this, however to get a feel for threads I'm trying to display a simple progress display using a pthread. The problem is that the thread executes AFTER the compression is complete. Here is my program:

    void* compressShow(void *)
    {
        pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
        pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);

    cout<<"Compressing";

    while(1)
    {
        sleep(1);
        cout<<".";  
        sleep(1);
        cout<<".";
        sleep(1);
        cout<<".";
        sleep(1);
        cout<<".";  
        cout<<"\b\b\b\b";
    }

}

void compression(char *buffer, ofstream &outFile)
{
    //Some Compression code. Function executes each time a new line is lifted off the file. 
}  

int main(int argc, char *argv[])
{   

    if(argc < 3)
    {
        cout<<"You entered an insufficient number of command line arguments."<<endl;
    }

    else
    {
        ifstream inFile;
        inFile.open(argv[1], ios::in);
        ofstream outFile(argv[2]);

        char buffer[100] = {NULL};

        pthread_t thread;
        pthread_attr_t attribute;

        pthread_attr_init(&attribute);
        pthread_attr_setdetachstate(&attribute, PTHREAD_CREATE_DETACHED);

        pthread_create(&thread, &attribute, compressShow, (void *)5);

        while(inFile.good())
        {
     `     inFile.getline(buffer, 100, '\n');
           compression(buffer, outFile);
        }

        pthread_cancel(thread);
        //pthread_join(thread, NULL);
    }

    return 0;

}

Since I'm creating the thread BEFORE the while loop, I expect it to run concurrently with the loop that is doing the compression.

4

1 回答 1

1

This has nothing to do with threads. See the same effect with

int main()
{
    compressShow(0);
}

Try sending the flush manipulator from time to time.

于 2013-03-30T20:03:59.057 回答