Let's say I have a double pointer to a structure in main (i.e. an array of pointers to a struct) and I want to pass it to a function, where it will be filled. Let's say I would like to pass every "output" to the function with a "&" in front, so that it's clear which parameters are outputs. This would mean that in the function I have to deal with a triple pointer.
void fillarray(int elements, struct MyStruct *** array, int * output) {
// fill the array
// (see below)
// return output
*output = ...
}
int main() {
// some code
// ...
int elements_count = 10;
int some_int_output;
struct MyStruct ** = malloc(elements_count * sizeof(struct MyStruct *));
for (i = 0; i < elements_count; i++) {
array_of_pointers[i] = malloc(sizeof(struct MyStruct));
fillarray(elements_count, &array_of_pointers, &some_int_output);
// some code
// ...
}
Now I would like to access (and fill) the array inside the function using an array notation:
for (i = 0; i < elements; i++) {
*array[i] = ... // ONLY WORKS FOR i=0 THEN SEGFAULT
}
in analogy to how I return an integer output (*output = ...).
Instead I found that the only (?) way to access it would be:
for (i = 0; i < elements; i++) {
*(*array + i) = ... // WORKS FOR ALL ELEMENTS
}
I think the problem has to do with which "pointer dimension" gets dereferenced first, so that *array[i] does not access the intended memory while *(*array + i) does. Using this second notation would make things more complicated and error-prone, offsetting the (supposed) advantage of having the "&" in the function call.
Does anyone have a suggestion on how to better re-write this, in order to use an array notation inside the function, while keeping the triple pointer? Is there a way to influence the "pointer dimension order"?
Thanks in advance.
PS I am aware there are (many) other ways of achieving the same result and I have successfully used a few of them. Here I was interested in knowing if the above conditions could be satisfied, while learning more about pointers.
