Stack based allocation not recommended?

The libmemcached documentation has this note:

You may wish to avoid using memcached_create(3) or memcached_clone(3) with a stack based allocation. The most common issues related to ABI safety involve heap allocated structures.

How do I have to understand it? Stands in this case ABI for Application Binary Interface? I would like to provide the pointer to the struct for memcached_clone() from a variable in the local function scope. Is it safe?

Example - is this code OK?

foo()
{
   memcached_st clone_memc;

   memcached_clone(&clone_memc, master_memc);

   // some memcache function calls (get/set)
   ...

   memcached_free(&clone_memc);
}