Pthreads将void *参数转换为int数组

Question

I'm dealing with this code written in c++:

int *V;
V = new int[nfilas*ncols];
iret=pthread_create(&threadList[i], NULL, worker_function, (void*)(&V)[nfilas*ncols]);

that passes "V" (a int array) to this function:

    int *matrix=(int*)ptr;
    for( int r=0; r<nfilas; ++r ){
    for( int c=0; c<ncols; c++ ){
        printf("%d ", matrix[r*ncols+c]);
    }

My problem is that i can't convert that void pointer into an array of int elements. How can i solve this? I've try many thing but I don't know what I'm doing wrong. Thank you in advance

Answer 1

You've got too much going on in your cast…

Spawn your thread with pthread_create(..., V); // V is already a pointer pthread_create(..., V); // V is already a pointer

Answer 2

You can safely cast from int * to void * and back...

int *V;
V = new int[nfilas*ncols];
iret = pthread_create(
    &threadList[i], NULL, worker_function, static_cast<void *>(V));

In your function...

int *matrix = static_cast<int *>(ptr);
for(int r = 0; r < nfilas; r++){
    for(int c = 0; c < ncols; c++){
        printf("%d ", matrix[r*ncols+c]);
    }
}