mod_slotmem_plain
Slot-based shared memory provider.
Extension
mod_slotmem_plain.c
slotmem_plain_module

`mod_slotmem_plain` is a memory provider which provides for creation and access to a plain memory segment in which the datasets are organized in "slots."

If the memory needs to be shared between threads and processes, a better provider would be mod_slotmem_shm.

`mod_slotmem_plain` provides the following API functions:

apr_status_t doall(ap_slotmem_instance_t *s, ap_slotmem_callback_fn_t *func, void *data, apr_pool_t *pool)
  call the callback on all worker slots
apr_status_t create(ap_slotmem_instance_t **new, const char *name, apr_size_t item_size, unsigned int item_num, ap_slotmem_type_t type, apr_pool_t *pool)
  create a new slotmem with each item size is item_size.
apr_status_t attach(ap_slotmem_instance_t **new, const char *name, apr_size_t *item_size, unsigned int *item_num, apr_pool_t *pool)
  attach to an existing slotmem.
apr_status_t dptr(ap_slotmem_instance_t *s, unsigned int item_id, void**mem)
  get the direct pointer to the memory associated with this worker slot.
apr_status_t get(ap_slotmem_instance_t *s, unsigned int item_id, unsigned char *dest, apr_size_t dest_len)
  get/read the memory from this slot to dest
apr_status_t put(ap_slotmem_instance_t *slot, unsigned int item_id, unsigned char *src, apr_size_t src_len)
  put/write the data from src to this slot
unsigned int num_slots(ap_slotmem_instance_t *s)
  return the total number of slots in the segment
apr_size_t slot_size(ap_slotmem_instance_t *s)
  return the total data size, in bytes, of a slot in the segment
apr_status_t grab(ap_slotmem_instance_t *s, unsigned int *item_id);
  grab or allocate the first free slot and mark as in-use (does not do any data copying)
apr_status_t fgrab(ap_slotmem_instance_t *s, unsigned int item_id);
  forced grab or allocate the specified slot and mark as in-use (does not do any data copying)
apr_status_t release(ap_slotmem_instance_t *s, unsigned int item_id);
  release or free a slot and mark as not in-use (does not do any data copying)