quick start

#define POOLARRAY_IMPL

One source file in your project (only one) must define this to include the actual code for the functions.

assuming you have an array of struct

typedef struct testItem {
    int ttl;    // time to live
    int id;
} testItem;

first initialise the pool

PoolArray pool;             // the pool to manage the array
testItem items[poolSize];   // the array we're managing

// you MUST check the return value
if (!PoolArrayInit(&pool, &items, sizeof(testItem), poolSize)) {
    printf("unable to initialise pool array\n");
    return -1;
}

When you need to use an item in the pool

testItem* it = PoolArrayGetNextItem(&pool);
if (it == NULL) {
    printf("!!!! Pool used up couldn't grab a new item\n");
} else {
    // set up the new item...
}

when you need to update your active item in the pool you can use a simple for loop

for(PoolArrayNode* node = pool.activeList; node; node = node->next) {
    testItem* item = (testItem*)node->userData;
    ...
}

however if you need to retire a node within a loop you must first find out the next node...

PoolArrayNode* node = pool.activeList;
while( node ) {
    // update the item
    testItem* item = (testItem*)node->userData;
    PoolArrayNode* nextNode = node->next;
    ...
    
    if (checkItem(item)) {
        PoolArrayRetireNode(&pool, node);
    }
    node = nextNode;
}

don't forget to destroy the pool when you have finished with it...