I have two integer pointers, a and b. I use the following line:
int* b = malloc(3 * sizeof(int));
I expect calling sizeof(b) to return 3 * sizeof(int) which equals 12, but that isn’t the case and it returns 8.
To a I would like to allocate the elements present in b, with another element appended (at the end of it). If advice is given regarding how to allocate multiple, it would be appreciated.
My questions, summarised are:
Why is malloc showing the behaviour described in the first paragraph and
how to essentially append to an integer array
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to allocate the elements present in b, with another element appended
// Allocate
int *a = malloc(4 * sizeof(int));
// or better as
int *a = malloc(sizeof a[0] * 4);
// Copy the data pointed to by `b` to `a`.
memcpy(a, b, sizeof a[0] * 3);
// Assign.
a[3] = 42;
Try
void* b = malloc(3 * sizeof(int));
std::cout << "_msize: " << _msize(b);
int a[3]; //implicit malloc of 3 * int
std::cout << "size: " << sizeof(a);
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