is memset() more efficient than for loop in C?

Question

is memset more efficient than for loop. so if i have

char x[500];
memset(x,0,sizeof(x));

or

char x[500];
for(int i = 0 ; i &         


        

Answer 1

void fill_array(void* array, size_t size_of_item, size_t length, void* value) {
  uint8_t* bytes      = value;
  uint8_t  first_byte = bytes[0];

  if (size_of_item == 1) {
    memset(array, first_byte, length);
    return;
  }

  // size_of_item > 1 here.
  bool all_bytes_are_identical = true;

  for (size_t byte_index = 1; byte_index < size_of_item; byte_index++) {
    if (bytes[byte_index] != first_byte) {
      all_bytes_are_identical = false;
      break;
    }
  }

  if (all_bytes_are_identical) {
    memset(array, first_byte, size_of_item * length);
    return;
  }

  for (size_t index = 0; index < length; index++) {
    memcpy((uint8_t*)array + size_of_item * index, value, size_of_item);
  }
}

memset is more efficient, it shouldn't care about non symmetric values (where all_bytes_are_identical is false). So you will search how to wrap it.

This is my variant. It is working for both little and big endian systems.