Posix Pthread互斥

我在代码的注释中写了我的问题。Posix Pthread互斥

我想通过使用pthreads使我的代码并行。首先，我想通过多个线程并行地在内存中写入大量数据。写入数据后，我想通过相同的线程执行这些数据。在执行数据后，我想阅读它。这三个操作之后，我想将这些数据传递给其他文件。我想多次重复这个过程。

我真的很感激你的任何帮助。谢谢。

#include <pthread.h> 
#include <stdio.h> 

#define ARRAYSIZE 100 
#define NUMTHREADS 7 

struct ThreadData { 
    int start, stop, id; 
    int* array; 
}; 

/* function to write, execute and read data */ 
void* cal(void* td) { 
    struct ThreadData* data=(struct ThreadData*) td; 
    int start=data->start; 
    int stop=data->stop; 
    int thread_id = data ->id; 
    int i,s, counter; 
    counter = 0; 

    //main loop 
    for (s=0; s<200; s++){ 

     // in this loop1, I want to write data here by all the threads 
     for (i=start; i<stop; i++) { 
    printf("thread %d is writing data\n", thread_id); 
     } 

     //in this loop2, after data written by all the threads in loop1, 
     // data is execuated by all threads in this loop2 
     for (i=start; i<stop; i++) { 
    printf("thread %d is executing data\n", thread_id); 
     } 

     //in this loop3, data is read after completion of 
     // writing and execution in loop1 and loop2 
     for (i=start; i<stop; i++) { 
    printf("thread %d is reading data\n", thread_id); 
     } 

     // counter, I want this counter to be executed only once 
     // per iteration after writing, executing and reading data. 
     counter = counter +1; 
    printf ("Value of counter is %d\n", counter); 

    } 

    return NULL; 
} 

int main(void) { 
    int array[ARRAYSIZE]; 
    pthread_t thread[NUMTHREADS]; 
    struct ThreadData data[NUMTHREADS]; 
    int i; 

    int tasksPerThread=(ARRAYSIZE+NUMTHREADS-1)/NUMTHREADS; 

    /* Divide work for threads, prepare parameters */ 
    for (i=0; i<NUMTHREADS; i++) { 
     data[i].start=i*tasksPerThread; 
     data[i].stop=(i+1)*tasksPerThread; 
     data[i].array=array; 
     data[i].id = i; 
    } 
    /* the last thread must not go past the end of the array */ 
    data[NUMTHREADS-1].stop=ARRAYSIZE; 

    /* Launch Threads */ 
    for (i=0; i<NUMTHREADS; i++) { 
     pthread_create(&thread[i], NULL, cal, &data[i]); 
    } 

    /* Wait for Threads to Finish */ 
    for (i=0; i<NUMTHREADS; i++) { 
     pthread_join(thread[i], NULL); 
    } 

    return 0; 
}

来源

2014-02-17 HKK

我认为你可以通过使用信号量来做到这一点（http://www.csc.villanova.edu/~mdamian/threads/posixsem.html） –

但我认为你应该为每个循环使用不同的线程。 –

另外请注意，阅读你不需要互斥 –

我想你需要互斥仅供计数器，以便做之前，线程同步步骤，这应该是足够的。

来源

2014-02-17 18:54:14 DAS

Posix Pthread互斥

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