Question

I have this function defined:

struct heap_validation {
    size_t num_alloc;
    size_t num_alloc_sz;
    struct memory *mem;
};
...
bool get_isallocated(struct metadata_record *);

When I call the heap_validation function from hashtable_traverse and print the result, I’ve gotten the following values: 0,255 ,246

void hashtable_traverse(struct metadata_record *metarec,
        struct heap_validation *heap_val) {

    printf("get_isallocated(metarec): %d\n",get_isallocated(metarec));

    bool retrieved = false;
    bool allocated = get_isallocated(metarec);
    if (allocated) {
        heap_val->num_alloc += 1;

I also tried with %d and I get the same result.

Answer 1

It turns out that the function hashtable_traverse, which is the function called by the GLib’s g_hash_table_foreach() to iterate over a GHashTable, expects both the key and value.

I only had the value and a pointer to user data.

• metarec is the value.
• The key should be an address pointer (1st parameter), and heap_val is user data, which is optional in g_hash_table_foreach()