在OpenMP中将数组声明为firstprivate-C

Question

I'm beginning to dive into OpenMP and I'm not sure I fully understand how firstprivate would deal with arrays.

If I had code such as:

int array[5] = {0, 1, 2, 3, 4};
int i;    
#pragma omp parallel for firstprivate(array)
for (i=0; i<SOME_LENGTH; i++) {
  // something using array as a right hand operand
}

Would the array be copied to each thread? What if it was a more complex structure and not a simple int ?

Is the memory itself copied or the values?

Also if you can point me in the direction of more documentation I would really appreciate it.

Thanks!

Answer 1

Yes, each thread gets its own instance of the variable, initialized to the value of that variable.

Documentation seems to be a bit sparse beside the original documentation and some basic tutorials.

Answer 2

As per 2.15.3.4 of OpenMP 4.5 , the elements are copied:

For an array of elements of non-array type, each element is initialized as if by assignment from an element of the original array to the corresponding element of the new array.