Dynamically growing an array using realloc() is error prone and boring.

Define your array with:

Then before adding n`th element to the item, call `ALLOC_GROW(item, n, alloc). This ensures that the array can hold at least n elements by calling realloc(3) and adjusting alloc variable.

sometype *item;
size_t nr;
size_t alloc

for (i = 0; i < nr; i++)
	if (we like item[i] already)

/* we did not like any existing one, so add one */
ALLOC_GROW(item, nr + 1, alloc);
item[nr++] = value you like;

You are responsible for updating the nr variable.

If you need to specify the number of elements to allocate explicitly then use the macro REALLOC_ARRAY(item, alloc) instead of ALLOC_GROW.