Question

所以我正在开发一个程序，我正在使用pthreads并行解决问题。现在，当我在函数中运行以下代码时，我遇到了一个seg错误：average_power。

这是代码的相关部分，我很确定错误在某处：

struct args {
      signal *sigs;
      int filter_orders;
      double *filter_coeffss;
      signal *outputs;
      int threadIDs;
      int bandwidths;
      int bandNumbers;
};

double *band_power; 
pthread_t *tid;  // array of thread ids
int numThread;
int numProc;

void *worker(void *arg){
     struct args *currentArgs = (struct args*) arg;
     int i;
     int blocksize = currentArgs->bandNumbers / numThread; // note: floor

     int mystart, myend;
     int currentID = currentArgs->threadIDs;
     int band;
     int bandwidth = currentArgs->bandwidths;

     mystart = currentID*blocksize;
     if (currentID==(numThread-1)) { // last processor
         // the last processor will take care of the leftover
         // elements of the vector, in case num_threads doesn't
         // divide vector_len
         myend = currentArgs->bandNumbers;
     } else {
         myend = (currentID+1) * blocksize;
     }

     cpu_set_t set;
     CPU_ZERO(&set);
     CPU_SET(currentID%numProc,&set);
     if (sched_setaffinity(0,numProc,&set)<0) { // do it
              perror("Can't setaffinity");  // hopefully doesn't fail
              exit(-1);
     }

     //THIS LOOP WILL BE THE NEW WORKER PROCESS TO BE SPLIT UP VIA BANDS
     for (band=mystart;band<myend;band++) { 
     // Make the filter
         generate_band_pass(currentArgs->sigs->Fs, 
           band*bandwidth+0.0001, // keep within limits
           (band+1)*bandwidth-0.0001,
           currentArgs->filter_orders, 
           currentArgs->filter_coeffss);
         hamming_window(currentArgs->filter_orders,currentArgs->filter_coeffss);

    // Convolve
         convolve(currentArgs->sigs->num_samples,
            currentArgs->sigs->data,
            currentArgs->filter_orders,
            currentArgs->filter_coeffss,
            currentArgs->outputs->data);

    // Capture characteristics
         band_power[band] = avg_power(currentArgs->outputs->data,      currentArgs->outputs->num_samples);
     }

     pthread_exit(NULL); 
}

这就是worker函数以及从另一个函数的这一部分传递给它的struct args，其中线程被初始化并给出指令：

band_power = (double *) malloc(sizeof(double)*numThread);
    tid = (pthread_t *) malloc(sizeof(pthread_t)*numThread);

    ///create all structs and initialize
    struct args *curargs;
    int p;
    int num_started;
    for(p=0;p<numThread;p++){
        outputNew = (struct signal *) malloc(sizeof(struct signal)); //THIS IS THE LINE THAT 

        outputNew = allocate_signal(sig->num_samples, sig->Fs, 0);
        curargs = (struct args *) malloc(sizeof(struct args));
        curargs->sigs = sig;
        curargs->filter_orders = filter_order;
        curargs->filter_coeffss = filter_coeffs;
        curargs->outputs = outputNew;
        curargs->threadIDs = p;
        curargs->bandwidths = bandwidth;
        curargs->bandNumbers = num_bands;
        rc=pthread_create( &(tid[p]), // thread id gets put here
               NULL,      // use default attributes
               worker,    // thread will begin in this function
               curargs  // we'll give it i as the argument
                 );
        if (rc==0) { 
            printf("Started thread %ld, tid %lu\n",p,tid[p]);
            num_started++;
        } else {
            printf("Failed to start thread %ld\n",p);
            perror("Failed to start thread");
            tid[p]=0xdeadbeef;
        }

所以我得到的错误是在* worker（average_power正确，我已经证明是forsure）调用average_power时其中一个线程内的段错误，或者当我取消注释时我得到一个错误我的循环中的以下行初始化数组。

outputNew = (struct signal *) malloc(sizeof(struct signal));

我想确保在它被放入arg结构之前的outputNew有自己的空间，所以它不会被覆盖，但是这一行不让它编译。我没有这样做吗？否则average_power从args结构中访问这个变量（输出），当发生这种情况时它会得到一个段错误，我认为这意味着某些内存没有被正确使用？对不起，如果这么长，如果我没有说得好，我可以澄清任何部分。所有其他函数或对事物的调用都与我的项目有关，我知道这些是正确的，我的错误来自我的pthread实现并将数据传递到某个地方。

Answer 1

我没有看到变量outputNew在任何地方声明。也许不是

outputNew = (struct signal *) malloc(sizeof(struct signal));

你的意思是：

struct signal *outputNew = malloc(sizeof(struct signal));

分段错误或SizeOf未正确使用

1 个答案: